Pectin Substances-Plant Gums

Pectin is a polymer of α-Galacturonic acid with a variable number of methyl ester groups

Methylated ester of Polygalacturonic acid

Chains of 300 to 1000 glalacturonic acid units

Joined with 1αrarr4 linkages

This structure shown here is three methyl ester forms (-COOCH3) for every

two carboxyl groups (-COOH)

hence it is has a 60 degree of esterification normally called a DE-60 pectin

The Degree of Esterification (DE) affects the gelling properties of pectin

Pectic Substance Nomenclature

1048721Protopectin

ndash Immature plant material

1048721Pectinic acid

ndash Mature plant material

1048721Pectin

ndash Mature plant material

1048721Pectic Acid

ndash Overripe plant material

1048721 Protopectin- high methyl ester content1048721 Pectinic acid-intermediate methyl ester content solublendash Salts are pectinates1048721 Pectin-intermediate methyl ester content colloidal1048721 Pectic Acid-little methyl ester contentndash Salts are pectates

Proto-pectin reaches its maximum quantity in fruits just before picking

time During ripening it is changed by enzymes into pectin and pectinic

acid and finally into pectic acid

It can be readily understood how the fruits become softer and more

juicy as the adhesive between the cells breaks down

The only substance which enters into jelly formation is pectin and it is

therefore of paramount importance to obtain and preserve as much of this

from the fruit as possible

The fruit should be in sound condition and not over ripe so that when the

fruit is cooked in the factory as much pectin as possible is obtained

As the amount and quality of the pectin obtained is extremely variable it

is common practice in order to produce a uniform product to add during

manufacture pectin extracts of standardized strength obtained from apples

or citrus fruits

Pectin dissolves in water Due to the high water content of the fruit mass

a hydration layer is formed around the pectin molecules Therefore the

pectin molecules can not move freely and can not come close enough to

each other to bind Underripe fruits have more pectin as fruit ripens the pectin changes to a non-gelling form

Besides this the free carboxyl groups are dissociated H+ is loosened

a negative end is the result This results in a negative charge of pectin

molecules A negative charge makes the molecules depart from each

other Binding is impossible

Sugar binds water and takes water from the hydration layer

Hydration layer gets thinner and the pectin molecules can move more

freely But the negative charge is actually still very high so the

molecules keep pushing off each other When the acid is added the pH

drops under 35 The positive hydrogen molecules bind the dissociated

groups The negative charge gets more neutral and the pectin molecule

can approach each other so they can bind at several places (The pectin

conglomerates and forms a network of fibers traps the fruit juice or

other liquid much like a sponge absorbs water) This enables a gel to

form

The optimum sugar concentration is about 675 per cent although with

increased pectin and acid jellies can be formed with 60 per cent sugar

Normally 05 per cent to 10 per cent pectin is used in jam

manufacture

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar has the property of stabilizing the

supersaturated solution of sucrose and so reducing the tendency to grain

(discourages sugar crystallization in the jelly)

In the right proportion pectin sugar and acid will form a gel in the

cold This is not possible with cooked pulp without driving off a

considerable amount of the water present This is done after the addition

of sugar by boiling in steam jacketed pans

Sweet spreads (The term sweet spreads covers a wide variety of

products in which the main ingredients are sugar and fruit)

ndashbutters jellies jams conserves marmalades and preservesndashadd zest

to meals They can be made from fruit that is not completely suitable for

canning or freezing All contain the four essential ingredients needed to make a jellied

fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of

different ingredients method of preparation and density of the fruit

pulp Jam and jelly are two different types of fruit preserves (Fruit

preserves are fruits or vegetables that have been prepared and

canned for long term storage)

and the difference between jam and jelly is actually quite significant

in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the

contents Jam is made from whole fruit (fruit pulp) meaning every edible

part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more

evenly-textured spread Because jam includes whole fruit it tends to have more of the

vitamins and minerals found in the parent fruit and it is also usually

only made with one type of fruit whereas jellies may involve a blend

of juices There is also a difference between jam and jelly in terms of

preparation methods

Jam is made by cooking fruit with sugar and water until the fruit

starts to soften and break up releasing its natural pectin Pectin is the

substance which makes jam firm up into a gelatinous solid Once the

fruit is softened the jam can be canned and sealed with some cooks

processing their jam to make the texture more uniform

Jelly can be made with fruit juice or with liquid leftover from

making jam Because whole fruit is not involved pectin must be

added to jelly to ensure that it firms Unlike jelly jam does not need

added pectin illustrating a major difference between jam and jelly

Today the general definition for marmalade is a sweet jelly in

which pieces of fruit and rind are suspended The key is the rind

which gives lends a bitterness to delightfully balance the sweetness

of the jelly Most marmalades have a citrus base either orange

(preferably Seville orange) lime lemon grapefruit or kumquat

FRUIT AND ITS PREPARATION

Important considerations in jam making

Type or variety of fruit

Conditions of the fruit

Suitability for transport and in preparation

Pectin content

High pectin fruits are apples crab apples quinces red currants

gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots

cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-

pectin fruits or with a commercial pectin When a commercial pectin is

added fully ripe fruit can be used The use of this added pectin also

increases the yield from a recipe

Strawberries

Strawberries are of better quality in England than in any other country

in the world and are in great demand for jam making

Strawberries are easily bruised and then the juice rapidly drains away

involving heavy losses in weight and flavor For this reason they should

be picked just before they are fully ripe

One of the major problems in handling strawberries is the removal of

the stalk and plug This is an operation which can only be done by hand

and is usually performed by women sometimes on a site near the field

but usually in the jam factory

Plugged strawberries should be processed immediately as they

quickly deteriorate

Any dirt or grit should also be removed and this can be done by

spraying with water

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Pectic Substance Nomenclature

1048721Protopectin

ndash Immature plant material

1048721Pectinic acid

ndash Mature plant material

1048721Pectin

ndash Mature plant material

1048721Pectic Acid

ndash Overripe plant material

1048721 Protopectin- high methyl ester content1048721 Pectinic acid-intermediate methyl ester content solublendash Salts are pectinates1048721 Pectin-intermediate methyl ester content colloidal1048721 Pectic Acid-little methyl ester contentndash Salts are pectates

Proto-pectin reaches its maximum quantity in fruits just before picking

time During ripening it is changed by enzymes into pectin and pectinic

acid and finally into pectic acid

It can be readily understood how the fruits become softer and more

juicy as the adhesive between the cells breaks down

The only substance which enters into jelly formation is pectin and it is

therefore of paramount importance to obtain and preserve as much of this

from the fruit as possible

The fruit should be in sound condition and not over ripe so that when the

fruit is cooked in the factory as much pectin as possible is obtained

As the amount and quality of the pectin obtained is extremely variable it

is common practice in order to produce a uniform product to add during

manufacture pectin extracts of standardized strength obtained from apples

or citrus fruits

Pectin dissolves in water Due to the high water content of the fruit mass

a hydration layer is formed around the pectin molecules Therefore the

pectin molecules can not move freely and can not come close enough to

each other to bind Underripe fruits have more pectin as fruit ripens the pectin changes to a non-gelling form

Besides this the free carboxyl groups are dissociated H+ is loosened

a negative end is the result This results in a negative charge of pectin

molecules A negative charge makes the molecules depart from each

other Binding is impossible

Sugar binds water and takes water from the hydration layer

Hydration layer gets thinner and the pectin molecules can move more

freely But the negative charge is actually still very high so the

molecules keep pushing off each other When the acid is added the pH

drops under 35 The positive hydrogen molecules bind the dissociated

groups The negative charge gets more neutral and the pectin molecule

can approach each other so they can bind at several places (The pectin

conglomerates and forms a network of fibers traps the fruit juice or

other liquid much like a sponge absorbs water) This enables a gel to

form

The optimum sugar concentration is about 675 per cent although with

increased pectin and acid jellies can be formed with 60 per cent sugar

Normally 05 per cent to 10 per cent pectin is used in jam

manufacture

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar has the property of stabilizing the

supersaturated solution of sucrose and so reducing the tendency to grain

(discourages sugar crystallization in the jelly)

In the right proportion pectin sugar and acid will form a gel in the

cold This is not possible with cooked pulp without driving off a

considerable amount of the water present This is done after the addition

of sugar by boiling in steam jacketed pans

Sweet spreads (The term sweet spreads covers a wide variety of

products in which the main ingredients are sugar and fruit)

ndashbutters jellies jams conserves marmalades and preservesndashadd zest

to meals They can be made from fruit that is not completely suitable for

canning or freezing All contain the four essential ingredients needed to make a jellied

fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of

different ingredients method of preparation and density of the fruit

pulp Jam and jelly are two different types of fruit preserves (Fruit

preserves are fruits or vegetables that have been prepared and

canned for long term storage)

and the difference between jam and jelly is actually quite significant

in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the

contents Jam is made from whole fruit (fruit pulp) meaning every edible

part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more

evenly-textured spread Because jam includes whole fruit it tends to have more of the

vitamins and minerals found in the parent fruit and it is also usually

only made with one type of fruit whereas jellies may involve a blend

of juices There is also a difference between jam and jelly in terms of

preparation methods

Jam is made by cooking fruit with sugar and water until the fruit

starts to soften and break up releasing its natural pectin Pectin is the

substance which makes jam firm up into a gelatinous solid Once the

fruit is softened the jam can be canned and sealed with some cooks

processing their jam to make the texture more uniform

Jelly can be made with fruit juice or with liquid leftover from

making jam Because whole fruit is not involved pectin must be

added to jelly to ensure that it firms Unlike jelly jam does not need

added pectin illustrating a major difference between jam and jelly

Today the general definition for marmalade is a sweet jelly in

which pieces of fruit and rind are suspended The key is the rind

which gives lends a bitterness to delightfully balance the sweetness

of the jelly Most marmalades have a citrus base either orange

(preferably Seville orange) lime lemon grapefruit or kumquat

FRUIT AND ITS PREPARATION

Important considerations in jam making

Type or variety of fruit

Conditions of the fruit

Suitability for transport and in preparation

Pectin content

High pectin fruits are apples crab apples quinces red currants

gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots

cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-

pectin fruits or with a commercial pectin When a commercial pectin is

added fully ripe fruit can be used The use of this added pectin also

increases the yield from a recipe

Strawberries

Strawberries are of better quality in England than in any other country

in the world and are in great demand for jam making

Strawberries are easily bruised and then the juice rapidly drains away

involving heavy losses in weight and flavor For this reason they should

be picked just before they are fully ripe

One of the major problems in handling strawberries is the removal of

the stalk and plug This is an operation which can only be done by hand

and is usually performed by women sometimes on a site near the field

but usually in the jam factory

Plugged strawberries should be processed immediately as they

quickly deteriorate

Any dirt or grit should also be removed and this can be done by

spraying with water

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

The only substance which enters into jelly formation is pectin and it is

therefore of paramount importance to obtain and preserve as much of this

from the fruit as possible

The fruit should be in sound condition and not over ripe so that when the

fruit is cooked in the factory as much pectin as possible is obtained

As the amount and quality of the pectin obtained is extremely variable it

is common practice in order to produce a uniform product to add during

manufacture pectin extracts of standardized strength obtained from apples

or citrus fruits

Pectin dissolves in water Due to the high water content of the fruit mass

a hydration layer is formed around the pectin molecules Therefore the

pectin molecules can not move freely and can not come close enough to

each other to bind Underripe fruits have more pectin as fruit ripens the pectin changes to a non-gelling form

Besides this the free carboxyl groups are dissociated H+ is loosened

a negative end is the result This results in a negative charge of pectin

molecules A negative charge makes the molecules depart from each

other Binding is impossible

Sugar binds water and takes water from the hydration layer

Hydration layer gets thinner and the pectin molecules can move more

freely But the negative charge is actually still very high so the

molecules keep pushing off each other When the acid is added the pH

drops under 35 The positive hydrogen molecules bind the dissociated

groups The negative charge gets more neutral and the pectin molecule

can approach each other so they can bind at several places (The pectin

conglomerates and forms a network of fibers traps the fruit juice or

other liquid much like a sponge absorbs water) This enables a gel to

form

The optimum sugar concentration is about 675 per cent although with

increased pectin and acid jellies can be formed with 60 per cent sugar

Normally 05 per cent to 10 per cent pectin is used in jam

manufacture

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar has the property of stabilizing the

supersaturated solution of sucrose and so reducing the tendency to grain

(discourages sugar crystallization in the jelly)

In the right proportion pectin sugar and acid will form a gel in the

cold This is not possible with cooked pulp without driving off a

considerable amount of the water present This is done after the addition

of sugar by boiling in steam jacketed pans

Sweet spreads (The term sweet spreads covers a wide variety of

products in which the main ingredients are sugar and fruit)

ndashbutters jellies jams conserves marmalades and preservesndashadd zest

to meals They can be made from fruit that is not completely suitable for

canning or freezing All contain the four essential ingredients needed to make a jellied

fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of

different ingredients method of preparation and density of the fruit

pulp Jam and jelly are two different types of fruit preserves (Fruit

preserves are fruits or vegetables that have been prepared and

canned for long term storage)

and the difference between jam and jelly is actually quite significant

in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the

contents Jam is made from whole fruit (fruit pulp) meaning every edible

part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more

evenly-textured spread Because jam includes whole fruit it tends to have more of the

vitamins and minerals found in the parent fruit and it is also usually

only made with one type of fruit whereas jellies may involve a blend

of juices There is also a difference between jam and jelly in terms of

preparation methods

Jam is made by cooking fruit with sugar and water until the fruit

starts to soften and break up releasing its natural pectin Pectin is the

substance which makes jam firm up into a gelatinous solid Once the

fruit is softened the jam can be canned and sealed with some cooks

processing their jam to make the texture more uniform

Jelly can be made with fruit juice or with liquid leftover from

making jam Because whole fruit is not involved pectin must be

added to jelly to ensure that it firms Unlike jelly jam does not need

added pectin illustrating a major difference between jam and jelly

Today the general definition for marmalade is a sweet jelly in

which pieces of fruit and rind are suspended The key is the rind

which gives lends a bitterness to delightfully balance the sweetness

of the jelly Most marmalades have a citrus base either orange

(preferably Seville orange) lime lemon grapefruit or kumquat

FRUIT AND ITS PREPARATION

Important considerations in jam making

Type or variety of fruit

Conditions of the fruit

Suitability for transport and in preparation

Pectin content

High pectin fruits are apples crab apples quinces red currants

gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots

cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-

pectin fruits or with a commercial pectin When a commercial pectin is

added fully ripe fruit can be used The use of this added pectin also

increases the yield from a recipe

Strawberries

Strawberries are of better quality in England than in any other country

in the world and are in great demand for jam making

Strawberries are easily bruised and then the juice rapidly drains away

involving heavy losses in weight and flavor For this reason they should

be picked just before they are fully ripe

One of the major problems in handling strawberries is the removal of

the stalk and plug This is an operation which can only be done by hand

and is usually performed by women sometimes on a site near the field

but usually in the jam factory

Plugged strawberries should be processed immediately as they

quickly deteriorate

Any dirt or grit should also be removed and this can be done by

spraying with water

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Besides this the free carboxyl groups are dissociated H+ is loosened

a negative end is the result This results in a negative charge of pectin

molecules A negative charge makes the molecules depart from each

other Binding is impossible

Sugar binds water and takes water from the hydration layer

Hydration layer gets thinner and the pectin molecules can move more

freely But the negative charge is actually still very high so the

molecules keep pushing off each other When the acid is added the pH

drops under 35 The positive hydrogen molecules bind the dissociated

groups The negative charge gets more neutral and the pectin molecule

can approach each other so they can bind at several places (The pectin

conglomerates and forms a network of fibers traps the fruit juice or

other liquid much like a sponge absorbs water) This enables a gel to

form

The optimum sugar concentration is about 675 per cent although with

increased pectin and acid jellies can be formed with 60 per cent sugar

Normally 05 per cent to 10 per cent pectin is used in jam

manufacture

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar has the property of stabilizing the

supersaturated solution of sucrose and so reducing the tendency to grain

(discourages sugar crystallization in the jelly)

In the right proportion pectin sugar and acid will form a gel in the

cold This is not possible with cooked pulp without driving off a

considerable amount of the water present This is done after the addition

of sugar by boiling in steam jacketed pans

Sweet spreads (The term sweet spreads covers a wide variety of

products in which the main ingredients are sugar and fruit)

ndashbutters jellies jams conserves marmalades and preservesndashadd zest

to meals They can be made from fruit that is not completely suitable for

canning or freezing All contain the four essential ingredients needed to make a jellied

fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of

different ingredients method of preparation and density of the fruit

pulp Jam and jelly are two different types of fruit preserves (Fruit

preserves are fruits or vegetables that have been prepared and

canned for long term storage)

and the difference between jam and jelly is actually quite significant

in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the

contents Jam is made from whole fruit (fruit pulp) meaning every edible

part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more

evenly-textured spread Because jam includes whole fruit it tends to have more of the

vitamins and minerals found in the parent fruit and it is also usually

only made with one type of fruit whereas jellies may involve a blend

of juices There is also a difference between jam and jelly in terms of

preparation methods

Jam is made by cooking fruit with sugar and water until the fruit

starts to soften and break up releasing its natural pectin Pectin is the

substance which makes jam firm up into a gelatinous solid Once the

fruit is softened the jam can be canned and sealed with some cooks

processing their jam to make the texture more uniform

Jelly can be made with fruit juice or with liquid leftover from

making jam Because whole fruit is not involved pectin must be

added to jelly to ensure that it firms Unlike jelly jam does not need

added pectin illustrating a major difference between jam and jelly

Today the general definition for marmalade is a sweet jelly in

which pieces of fruit and rind are suspended The key is the rind

which gives lends a bitterness to delightfully balance the sweetness

of the jelly Most marmalades have a citrus base either orange

(preferably Seville orange) lime lemon grapefruit or kumquat

FRUIT AND ITS PREPARATION

Important considerations in jam making

Type or variety of fruit

Conditions of the fruit

Suitability for transport and in preparation

Pectin content

High pectin fruits are apples crab apples quinces red currants

gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots

cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-

pectin fruits or with a commercial pectin When a commercial pectin is

added fully ripe fruit can be used The use of this added pectin also

increases the yield from a recipe

Strawberries

Strawberries are of better quality in England than in any other country

in the world and are in great demand for jam making

Strawberries are easily bruised and then the juice rapidly drains away

involving heavy losses in weight and flavor For this reason they should

be picked just before they are fully ripe

One of the major problems in handling strawberries is the removal of

the stalk and plug This is an operation which can only be done by hand

and is usually performed by women sometimes on a site near the field

but usually in the jam factory

Plugged strawberries should be processed immediately as they

quickly deteriorate

Any dirt or grit should also be removed and this can be done by

spraying with water

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

The optimum sugar concentration is about 675 per cent although with

increased pectin and acid jellies can be formed with 60 per cent sugar

Normally 05 per cent to 10 per cent pectin is used in jam

manufacture

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar has the property of stabilizing the

supersaturated solution of sucrose and so reducing the tendency to grain

(discourages sugar crystallization in the jelly)

In the right proportion pectin sugar and acid will form a gel in the

cold This is not possible with cooked pulp without driving off a

considerable amount of the water present This is done after the addition

of sugar by boiling in steam jacketed pans

Sweet spreads (The term sweet spreads covers a wide variety of

products in which the main ingredients are sugar and fruit)

ndashbutters jellies jams conserves marmalades and preservesndashadd zest

to meals They can be made from fruit that is not completely suitable for

canning or freezing All contain the four essential ingredients needed to make a jellied

fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of

different ingredients method of preparation and density of the fruit

pulp Jam and jelly are two different types of fruit preserves (Fruit

preserves are fruits or vegetables that have been prepared and

canned for long term storage)

and the difference between jam and jelly is actually quite significant

in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the

contents Jam is made from whole fruit (fruit pulp) meaning every edible

part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more

evenly-textured spread Because jam includes whole fruit it tends to have more of the

vitamins and minerals found in the parent fruit and it is also usually

only made with one type of fruit whereas jellies may involve a blend

of juices There is also a difference between jam and jelly in terms of

preparation methods

Jam is made by cooking fruit with sugar and water until the fruit

starts to soften and break up releasing its natural pectin Pectin is the

substance which makes jam firm up into a gelatinous solid Once the

fruit is softened the jam can be canned and sealed with some cooks

processing their jam to make the texture more uniform

Jelly can be made with fruit juice or with liquid leftover from

making jam Because whole fruit is not involved pectin must be

added to jelly to ensure that it firms Unlike jelly jam does not need

added pectin illustrating a major difference between jam and jelly

Today the general definition for marmalade is a sweet jelly in

which pieces of fruit and rind are suspended The key is the rind

which gives lends a bitterness to delightfully balance the sweetness

of the jelly Most marmalades have a citrus base either orange

(preferably Seville orange) lime lemon grapefruit or kumquat

FRUIT AND ITS PREPARATION

Important considerations in jam making

Type or variety of fruit

Conditions of the fruit

Suitability for transport and in preparation

Pectin content

High pectin fruits are apples crab apples quinces red currants

gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots

cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-

pectin fruits or with a commercial pectin When a commercial pectin is

added fully ripe fruit can be used The use of this added pectin also

increases the yield from a recipe

Strawberries

Strawberries are of better quality in England than in any other country

in the world and are in great demand for jam making

Strawberries are easily bruised and then the juice rapidly drains away

involving heavy losses in weight and flavor For this reason they should

be picked just before they are fully ripe

One of the major problems in handling strawberries is the removal of

the stalk and plug This is an operation which can only be done by hand

and is usually performed by women sometimes on a site near the field

but usually in the jam factory

Plugged strawberries should be processed immediately as they

quickly deteriorate

Any dirt or grit should also be removed and this can be done by

spraying with water

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Sweet spreads (The term sweet spreads covers a wide variety of

products in which the main ingredients are sugar and fruit)

ndashbutters jellies jams conserves marmalades and preservesndashadd zest

to meals They can be made from fruit that is not completely suitable for

canning or freezing All contain the four essential ingredients needed to make a jellied

fruit productndashfruit pectin acid and sugar They differ however depending upon fruit used proportion of

different ingredients method of preparation and density of the fruit

pulp Jam and jelly are two different types of fruit preserves (Fruit

preserves are fruits or vegetables that have been prepared and

canned for long term storage)

and the difference between jam and jelly is actually quite significant

in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the

contents Jam is made from whole fruit (fruit pulp) meaning every edible

part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more

evenly-textured spread Because jam includes whole fruit it tends to have more of the

vitamins and minerals found in the parent fruit and it is also usually

only made with one type of fruit whereas jellies may involve a blend

of juices There is also a difference between jam and jelly in terms of

preparation methods

Jam is made by cooking fruit with sugar and water until the fruit

starts to soften and break up releasing its natural pectin Pectin is the

substance which makes jam firm up into a gelatinous solid Once the

fruit is softened the jam can be canned and sealed with some cooks

processing their jam to make the texture more uniform

Jelly can be made with fruit juice or with liquid leftover from

making jam Because whole fruit is not involved pectin must be

added to jelly to ensure that it firms Unlike jelly jam does not need

added pectin illustrating a major difference between jam and jelly

Today the general definition for marmalade is a sweet jelly in

which pieces of fruit and rind are suspended The key is the rind

which gives lends a bitterness to delightfully balance the sweetness

of the jelly Most marmalades have a citrus base either orange

(preferably Seville orange) lime lemon grapefruit or kumquat

FRUIT AND ITS PREPARATION

Important considerations in jam making

Type or variety of fruit

Conditions of the fruit

Suitability for transport and in preparation

Pectin content

High pectin fruits are apples crab apples quinces red currants

gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots

cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-

pectin fruits or with a commercial pectin When a commercial pectin is

added fully ripe fruit can be used The use of this added pectin also

increases the yield from a recipe

Strawberries

Strawberries are of better quality in England than in any other country

in the world and are in great demand for jam making

Strawberries are easily bruised and then the juice rapidly drains away

involving heavy losses in weight and flavor For this reason they should

be picked just before they are fully ripe

One of the major problems in handling strawberries is the removal of

the stalk and plug This is an operation which can only be done by hand

and is usually performed by women sometimes on a site near the field

but usually in the jam factory

Plugged strawberries should be processed immediately as they

quickly deteriorate

Any dirt or grit should also be removed and this can be done by

spraying with water

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

and the difference between jam and jelly is actually quite significant

in terms of flavor texture and nutritional value The primary difference between jam and jelly involves the

contents Jam is made from whole fruit (fruit pulp) meaning every edible

part of the fruit is involved while jelly is made from fruit juices Jam is a thick chunky spread while jelly is a thinner more

evenly-textured spread Because jam includes whole fruit it tends to have more of the

vitamins and minerals found in the parent fruit and it is also usually

only made with one type of fruit whereas jellies may involve a blend

of juices There is also a difference between jam and jelly in terms of

preparation methods

Jam is made by cooking fruit with sugar and water until the fruit

starts to soften and break up releasing its natural pectin Pectin is the

substance which makes jam firm up into a gelatinous solid Once the

fruit is softened the jam can be canned and sealed with some cooks

processing their jam to make the texture more uniform

Jelly can be made with fruit juice or with liquid leftover from

making jam Because whole fruit is not involved pectin must be

added to jelly to ensure that it firms Unlike jelly jam does not need

added pectin illustrating a major difference between jam and jelly

Today the general definition for marmalade is a sweet jelly in

which pieces of fruit and rind are suspended The key is the rind

which gives lends a bitterness to delightfully balance the sweetness

of the jelly Most marmalades have a citrus base either orange

(preferably Seville orange) lime lemon grapefruit or kumquat

FRUIT AND ITS PREPARATION

Important considerations in jam making

Type or variety of fruit

Conditions of the fruit

Suitability for transport and in preparation

Pectin content

High pectin fruits are apples crab apples quinces red currants

gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots

cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-

pectin fruits or with a commercial pectin When a commercial pectin is

added fully ripe fruit can be used The use of this added pectin also

increases the yield from a recipe

Strawberries

Strawberries are of better quality in England than in any other country

in the world and are in great demand for jam making

Strawberries are easily bruised and then the juice rapidly drains away

involving heavy losses in weight and flavor For this reason they should

be picked just before they are fully ripe

One of the major problems in handling strawberries is the removal of

the stalk and plug This is an operation which can only be done by hand

and is usually performed by women sometimes on a site near the field

but usually in the jam factory

Plugged strawberries should be processed immediately as they

quickly deteriorate

Any dirt or grit should also be removed and this can be done by

spraying with water

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Jam is made by cooking fruit with sugar and water until the fruit

starts to soften and break up releasing its natural pectin Pectin is the

substance which makes jam firm up into a gelatinous solid Once the

fruit is softened the jam can be canned and sealed with some cooks

processing their jam to make the texture more uniform

Jelly can be made with fruit juice or with liquid leftover from

making jam Because whole fruit is not involved pectin must be

added to jelly to ensure that it firms Unlike jelly jam does not need

added pectin illustrating a major difference between jam and jelly

Today the general definition for marmalade is a sweet jelly in

which pieces of fruit and rind are suspended The key is the rind

which gives lends a bitterness to delightfully balance the sweetness

of the jelly Most marmalades have a citrus base either orange

(preferably Seville orange) lime lemon grapefruit or kumquat

FRUIT AND ITS PREPARATION

Important considerations in jam making

Type or variety of fruit

Conditions of the fruit

Suitability for transport and in preparation

Pectin content

High pectin fruits are apples crab apples quinces red currants

gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots

cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-

pectin fruits or with a commercial pectin When a commercial pectin is

added fully ripe fruit can be used The use of this added pectin also

increases the yield from a recipe

Strawberries

Strawberries are of better quality in England than in any other country

in the world and are in great demand for jam making

Strawberries are easily bruised and then the juice rapidly drains away

involving heavy losses in weight and flavor For this reason they should

be picked just before they are fully ripe

One of the major problems in handling strawberries is the removal of

the stalk and plug This is an operation which can only be done by hand

and is usually performed by women sometimes on a site near the field

but usually in the jam factory

Plugged strawberries should be processed immediately as they

quickly deteriorate

Any dirt or grit should also be removed and this can be done by

spraying with water

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

FRUIT AND ITS PREPARATION

Important considerations in jam making

Type or variety of fruit

Conditions of the fruit

Suitability for transport and in preparation

Pectin content

High pectin fruits are apples crab apples quinces red currants

gooseberries grapes plums and cranberries Low pectin fruits are strawberries blueberries peaches apricots

cherries pears raspberries blackberries and pineapple These low-pectin fruits should be combined with one of the high-

pectin fruits or with a commercial pectin When a commercial pectin is

added fully ripe fruit can be used The use of this added pectin also

increases the yield from a recipe

Strawberries

Strawberries are of better quality in England than in any other country

in the world and are in great demand for jam making

Strawberries are easily bruised and then the juice rapidly drains away

involving heavy losses in weight and flavor For this reason they should

be picked just before they are fully ripe

One of the major problems in handling strawberries is the removal of

the stalk and plug This is an operation which can only be done by hand

and is usually performed by women sometimes on a site near the field

but usually in the jam factory

Plugged strawberries should be processed immediately as they

quickly deteriorate

Any dirt or grit should also be removed and this can be done by

spraying with water

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Strawberries

Strawberries are of better quality in England than in any other country

in the world and are in great demand for jam making

Strawberries are easily bruised and then the juice rapidly drains away

involving heavy losses in weight and flavor For this reason they should

be picked just before they are fully ripe

One of the major problems in handling strawberries is the removal of

the stalk and plug This is an operation which can only be done by hand

and is usually performed by women sometimes on a site near the field

but usually in the jam factory

Plugged strawberries should be processed immediately as they

quickly deteriorate

Any dirt or grit should also be removed and this can be done by

spraying with water

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Where it is found necessary to transport strawberries over long

distances from the large growing areas to the big towns it is an

advantage to keep the fruit as cool as possible If packed in totally

enclosed trucks or wagons blocks of solidified carbon dioxide can be

used to reduce and maintain the temperature at about 400F for the

period of the journey

Raspberries

Raspberries are almost as popular as strawberries because of their

attractive flavor

Varieties Lloyd George and Norfolk Giant

They should be picked carefully without plugs when they are fully

ripe and converted to jam as quickly as possible

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Raspberries Blackcurrants

Gooseberries

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Sometimes raspberries will develop mould growth within a few hours

if they are moist and the weather is warm

Solid carbon dioxide can be use if fruits are in good condition and it

is necessary to store or transport overnight

For transport purposes casks are preferable to baskets as they prevent

wastage of juice

Blackcurrants

Fine flavor and high nutritional value

Most varieties of blackcurrants are suitable for jam making but the

best is probably ldquoBaldwinrdquo

The fruit usually arrives at the factory on stalks which can either be

removed by hand using a table fork to free the berries or by a strigging

machine

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Gooseberries

Gooseberries can produce a very excellent jam but there is only a

small demand for this preserve

The most important consideration for jam-making is the stage of

ripeness and they should always be picked when pale green

Ripe gooseberries lack the delicate flavor of the greener fruit They

produce a muddy colored jam and the skins are tough

Before cooking the tops and tails must be removed (snibbing

machine)

Water sprays help to remove the waste material and also to wash the

fruit

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Plums

Plums are very suitable for jam making as they contain both pectin and

acid in plenty

Size of plums plays an important part in their economic use since it is

better to use a large plum with a small stone than a small plum with a

large stone

Apples

Apples are never used alone in jam but they are very often a component

of mixtures of fruit

The green and hard type of apples are suitable not the soft kinds or

those with pink flesh

Citrus fruit

Citrus fruits are used for making marmalade

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

PRESERVATION OF FRUIT

Jam made from fresh fruit commands a higher price than that made

from preserved pulp

Very few factories are equipped to make all the fruit arriving during

the very short harvesting season into finished jam Even if it were

possible it is unlikely to be desirable to store such a large quantity of

finished goods

By preserving the fruit employment can be maintained throughout

the year

In times of glut when fruit is cheap enough pulp can be made to

ensure against a bad harvest

The commonest method of preserving jam fruit in Britain is by the

use of sulphurous acid but freezing or canning is used extensively in

USA

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

SO2 in the form of per cent solution in water is used as preservative

The main advantage of using sulfurous acid (for simplicity in the text

SO2 is used instead of sulfurous acid) as a chemical preservative is that

the bulk of it is driven off in the boiling process

Legal regulations require that there shall be not more than 40 ppm of

SO2 in the finished jam

In Great Britain SO2 is the only preservative used or permitted

The United States permits the use of SO2 or sodium benzoate if

declared

Australia New Zealand and many continental countries prohibit the

use of any preservative

Citrus fruits plums and blackcurrants are not seriously affected by

storage in SO2 but strawberries and raspberries lose their flavour and

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

sometimes completely disintegrate

Fruit can be preserved with SO2 either in the raw or cooked state

Strawberries raspberries and blackberries are best treated without

cooking whereas those with skins such as plums gooseberries black

and red currants are usually cooked before preserving as the storage in

SO2 tends to toughen the uncooked skins

The most convenient container for storage is the 40-gallon cask

Other methods such as glass containers or large concrete tanks are

used

If the fruit is to be preserved in the uncooked state it should be

carefully cleaned and prepared For every hundredweight of

strawberries to be placed in a cask frac12 gallon of fresh water is first put

into the unheaded container

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

The fruit is then added and then a final frac12 gallon of water per cwt is

poured in on top of the fruit This procedure helps to mix the fruit and

water as it is not possible to stir them up at all without breaking the

berries Raspberries and blackberries do not require any water When

the cask is full it can be headed up and placed on the roll Three pints of

6 per cent SO2 solution per cwt of fruit are then poured in through the

bunghole and the cask rolledPreparation of cooked fruit pulp

Cooking is the important step for the preparation of pulp

The cooking process in which the fruit is steamed for 10 to 20

mins should aim at bursting the skins but it should not be allowed to

break up the fruit into a mash destroying all the color and flavor

The cooking process should also serve to preserve the pectin

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

The old-fashioned method was to use steaming barrels but these

have been largely replaced by stainless steel pulping vats Near the

bottom of the vat is fitted a single coil of steam pipe which is

perforated every six inches to allow the steam to pass into the fruit

The amount of fruit and water must be carefully controlled and

also the weight of the finished batch so that the percentage of fruit in

the finished pulp is known when it is used for jam making

The cooked pulp is passed through the sieving machine and

collected in the receiving tank (Barrels can be filled from the tank as

required)

Hot pulp (those with skins such as plums gooseberries black and

red currants) are allowed to cool when 3 pints of SO2 solution are

added for each 1 cwt of pulp

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

JAM BOILING

The boiling of jam can be carried out either in

1) Small open pans

40 gallon capacity

Produces the higher quality jam

Common in Great Britain

Requires considerable skill and experience

2) or Large vacuum pans

A ton per charge

Used in USA

Emphasis on a high rate of production

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

Boiling is one of the most important steps in the jelly making

process as it dissolves the sugar and causes union of sugar acid and

pectin to form a jelly

It usually causes a coagulation of certain organic compounds that

can be skimmed from the surface during boiling and their removal

renders the jelly clearer

The principal purpose of boiling is to increase the concentration of

sugar to the point where jelling occurs

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

The sugar and water (about 1 gallon) are placed in the boiling pan

and heated together to dissolve the sugar

In some plants sugar syrup is made in a separate plant filtered

and pumped to the boiling pans

The fruit pulp and pectin are then added and the mixture

vigorously boiled until the temperature reached 2200F Boiling time

should be as short as possible and should never exceed ten minutes

Five to seven minutes is the optimum time Prolonged boiling

reduces the setting power of the pectin and yields dull-looking

caramelized jam with poor flavor It also creates an excessive

amount of invert sugar from which dextrose may crystallise out

The solids are then checked on the refractometer and as soon as

they reach 685 per cent the steam is turned off

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

It is essential in order to produce a jam of good quality and with

satisfactory keeping properties to boil to a soluble solids content 65

to 70 percent 685 per cent serves as a good end point for the jam

Where vacuum pans are used sugar water and pectin are heated

together to about 1400F in open pans The fruit is then added and

several batches of this mixture are transferred by suction to a large

vacuum pan where boiling is finished under a vacuum of 25 to 28

inches at a final temperature of 1400F

The ldquosettingrdquo of the jam is controlled by the pH of the boil All

ingredients fruit pulp sugar pectin and water affect the pH and

further adjustment can be made by the addition of citric acid either at

the beginning or the end of the boil A good gel is only obtained

when the pH lies between 30 and 32

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

The presence of acid both in the fruit and added separately causes

inversion of the sucrose in which one molecule of sucrose is converted

into one molecule of dextrose and one molecule of levulose which

constitutes invert sugar Invert sugar discourages the sugar

crystallization in the jelly

C12H22O11 ( sucrose) + H2O (water) = C6H12O6 (levulose) + C6H12O6

(dextrose)

The degree of inversion must be controlled to give a final invert sugar

content between 25 and 40 per cent If less than 25 per cent cane sugar

will crystallize If over 40 per cent dextrose may crystallize or the ldquosetrdquo

may be weak

Inversion of sugar is greatly affected by temperature It is therefore

important in the control of this factor that the jam should be cooled as

quickly as possible after boiling

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Slide 30

FINISHING AND STORING

The jam as it comes from the boiling pans will be at a temperature of

over 2120F and it must be cooled to 185oF to 190oF

This can be accomplished in tanks with double walls through which

cold water is flowing or in a revolving cylinder surrounded by a water

jacket

Filling

The cooled jam can be filled into containers either by hand or

machine

Hand filling is slow but is preferable where only small lots are being

made or large containers such as 28 Ib tins are required

Hand filling also avoids the breaking up of whole fruit which might

occur in a machine

The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
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The usual method of hand filling is on circular rotating tables The

jam is brought to the tables in bogies and poured into the jars which

are arranged around the edge of the table by means of a dipper

which has a funnel shaped end

After filling the operator makes the table rotate so that the filled

jars pass round to another worker

A disc of tissue is then laid flat on the surface The presence of the

disc of tissue is intended to prevent the condensation of moisture on

the surface of the jam This condensation would create localized

areas of low concentration in which mould would readily grow

For high rate of production a filling machine is indispensable

The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
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The jam is fed from the cooler into a sump from which it is drawn

by means of a double acting plunger-type pump which in turn

delivers it in fixed amounts to the filling nozzle of rotating head The

exact amount delivered can be adjusted by means of a hand wheel

which regulates the length of the stroke of the pump

• Pectin Substances-Plant Gums
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