ice cream namratha kollu - agrihortico · 2019. 12. 10. · ice cream • ice cream, kulfi,...

ICE CREAM

Namratha Kollu

Ice cream

• Different kinds of frozen deserts.

1. Dairy ice cream

2. Non dairy ice cream

3. Gelato

4. Frozen yoghurt

5. Milk ice

6. Sorbet

7. Sherbet

8. Water ice

9. Fruit ice

Ice cream

• Frozen Dessert / Frozen Confection(hereafter referred to as the said product) means the product obtained by freezing a

pasteurized mix prepared with milk fat and / or edible vegetable oils and fat having a melting point of not more than 37.0

degree C in combination and milk protein alone or in combination / or vegetable protein products singly or in combination

with the addition of nutritive sweetening agents e.g. sugar, dextrose, fructose, liquid glucose, dried liquid glucose,

maltodextrin, high maltose corn syrup, honey, fruit and fruit products, eggs and egg products coffee, cocoa, chocolate,

condiments, spices, ginger, and nuts. The said product may also contain bakery products such as cake or cookies as a separate

layer/or coating, it may be frozen hard or frozen to a soft consistency. It shall have pleasant taste and flavor free from off

flavor and rancidity and may contain food additives permitted

Ice cream

• Ice Cream, Kulfi, Chocolate Ice Cream or Softy Ice Cream(hereafter referred to as the said product) means the product

obtained by freezing a pasteurized mix prepared from milk and /or other products derived from milk with or without the

addition of nutritive sweetening agents, fruit and fruit products, eggs and egg products, coffee, cocoa, chocolate, condiments,

spices, ginger and nuts and it may also contain bakery products such as cake or cookies as a separate layer and/or coating.

The said product may be frozen hard or frozen to a soft consistency; the said product shall have pleasant taste and smell free

from off flavour and rancidity; the said product may contain food additives permitted

Ice cream

"ICE LOLLIES OR EDIBLE ICES" means the frozen ice produce which may contain sugar, syrup, fruit, fruit

juices, cocoa, citric acid, permitted flavors and colors. It may also contain permitted stabilizers and/or emulsifiers not

exceeding 0.5 per cent by weight. It shall not contain any artificial sweetner. Ice Candy means the product obtained by

freezing a pasteurized mix prepared from a mixture of water, nutritive sweeteners e.g. sugar, dextrose, liquid glucose,

dried liquid glucose, honey, fruits and fruit products, coffee, cocoa, ginger, nuts and salt. The product may contain food

additives permitted

It shall conform to the following requirement:—

Total sugars expressed as Sucrose ... Not less than 10.0 percent

• All the definitions are taken from the FSSA, ACT

Different classification of ice creams

Component Economy Standard Premium Super premium

Fat Legal Minimum usually 8-10% 10-12% 12-15% 15-18%

Total solids Legal Minimum usually 35-36% 36-38% 38-40% >40%

Over run Legal Maximum 100-120% 60-90% 25-50%

Ice cream

Different Ingredients in Ice cream and their functions and limitations

Constituent Functions Limitations

Milk Fat Increases the richness of flavor Relatively high cost

Lubricates and insulates the

mouth Smoothness of texture hinders whipping

May limit the consumption due to high calories and satiating effect

Non Dairy Fats

Provides good structure and

texture at lower cost than milk fat,

if appropriate solid fat content Contributes little to flavor and may impart the off flavors

May contribute to greasy texture

Milk solids not fat

Improves the body and texture

through emulsification and water

holding capacity High content may cause cooked or salty flavor

Whey protein

concentrates Promotes development of overrun Potential for sandiness (lactose crystallization) at high concentration

Whey solids

Less expensive than the

conventinal sources of MSNF High amount of lactose causes freezing point depression

Potential for sandiness greater than for conventional sources of MSNF



Sugar Lowers freezing point Excess sweetness possible

Imparts sweetness to the ice

cream Lower hardening temperature needed

Improves flavor/texture

Ice cream is softer , affecting scooping and the potential for greater

recrystallization

Corn syrup solids Lower cost than sugar Impart off flavor and chewy texture when overused

Improve body and texture

Increase the stability of ice cream

Stabilizer Enhance smooth texture Excess chewiness may occur

Provide body Increase the melt resistance

Enhance shelf life

Egg yolk solids Improve whipping ability Foamy melted product

Impart the custard flavor Egg flavor may be undesirable

Emulsifiers

Promote fat destabilization,

leading to dryness, smoothness

and good melting properties Increase potential for churning of fat



Total solids Smoother texture Heavy, soggy or sticky body

Firmer body Reduces coldness

High nutrient content

Lessen excess coldness

Flavoring Increases acceptability Intensities and harshness may be unacceptable

Coloring Improves attractiveness Artificial shades

Aids Flavor identification Allergic reactions

Dislike of consumers to added colors

Schematic diagram of ice cream processing:

Flow chart of ice cream processing

Points to be noted for mix

• MILK SOLIDS-NON-FAT (MSNF)

• MSNF consist of proteins, lactose and mineral salts

derived from whole milk, skim milk, condensed milk,

milk powders and/or whey powder. In addition to its

high nutritional value, MSNF helps to stabilize the

structure of ice cream due to its water-binding and

emulsifying effect. The same effect also has a

positive influence on air distribution in the ice cream

during the freezing process, leading to improved

body and creaminess.

In a well-balanced recipe, the quantity of MSNF

should always be in proportion to the water content.

The optimal level is 17 parts MSNF to 100 parts

water:

Standard formulations

The Mix Process:

High shear and High temperature(85 degree centigrade)

Formation of mix involves 3 major processes

1. Dispersion- High shear

2. Hydration of dry ingredients - High temperature

3. Emulsification

Ice cream

Ice cream

Order of addition :

1. Potable water

2. Emulsifier and stabilizer mix + sugar

3. Proteins

4. SMP

5. Remaining Sugar

6. Liquid Glucose

7. Fat

Ice cream

Double stage Homogenization Individual Homogenization

Homogenization:1. Stable suspension

2. Reduction of particle size of fat

• In the homogenizer the hot mix (> 70 C) is forced through a small valve under

high pressure (typically up to about 150 atm). The large fat droplets are

elongated and broken up into a fine emulsion of much smaller droplets (about

1 pm in diameter), greatly increasing the surface area of the fat.

• Sometimes a second homogenization step is used with a lower pressure

(about 35 atm) to reduce clustering of the small fat droplets after the first

stage.

• Recently, very high pressure homogenization (up to 2000 atm) has been

shown to produce even smaller fat droplets, and therefore a higher fat surface

area for a given volume.

• Proteins are very good at stabilizing oil-in-water emulsions against

coalescence because they provide a strong, thick membrane around the fat

droplet. Interactions between the proteins on the outside of the droplets make

it harder for the droplets to come into close contact. This is known as steric

stabilization.

Homogenization

Pasteurization:Minimal Time and Temperature combinations for ice cream mixes:

Source:Grade A Milk ordinance FDA , 2011

Ice cream

Ice cream

Schematic diagram of Pasteurization in Plate Heat Exchanger

Aging:

1. Temperature – 4 degree centigrade

2. Time - 4 hours to 24 hours.

•Emulsifiers adsorb to the surface of the fat droplets replacing

protein

•Crystallization of the fat

•Continuous re arrangement of the fat globules to form a

structure.

Ice cream

Freezing:Ice cream mix at approximately 4 degree C is pumped from the ageing

tank into the barrel, where it is aerated and frozen, before being pumped

out from the other end.

Ice cream

Cup filling

Cone filling

Cup and cone products:

Ice cream

Moulded Products:

Ice cream

Ice cream

Extruded Products:

Ice cream

New Developments in Vertical Extrusion:

Ice cream

Hardening:

•Quick hardening : -18 degree centigrade or preferably -25 degree

centigrade.

Ice cream

Qualitycontrolof ice creams

% Overrun = (Vol. of ice cream - Vol. of mix used)/Vol. of mix used x 100%

Example : 500 L mix gives 980 L ice cream,

(980 - 500)/500 x 100% = 96% Overrun

80 L mix plus 10 L chocolate syrup gives 170 L chocolate ice cream,

(Note : any flavors added such as this chocolate syrup which become

homogeneous with the mix can incorporate air and are thus accounted for in

this way : )

(170 - (80 + 10))/(80 + 10) x 100% = 88.8% Overrun

Over run:

Figuring plant overrun by volume, with particulates

Example : 40 L mix plus 28 L pecans gives 110 L butter pecan ice cream,

110 - 28 = 82 L actual ice cream.

% Overrun = (Vol. of ice cream - Vol. of mix used)/Vol. of mix used

= (82 - 40)/40 x 100% = 105%

(Note : The pecans do not incorporate air.)

Over run in presence of nuts:


Figuring density of mix:


Figuring mix density

The density of mix can be calculated as follows:

1 / ((% fat/100 x 1.075) + ((% T.S./100 - % Fat/100) x 0.63) + (% Water/100)) = Wt.

(kg)/ litre mix

Example - Calculate the weight per litre of mix containing 12% fat, 11% serum

solids, 10% sugar, 5% corn syrup solids, 0.30% stabilizer, and 38.3% T.S.

1.0 / ((0.12 x 1.075) + ((0.383 - 0.12) x 0.63) + 0.617) = 1.096 kg/L of mix

•Flavor defects

•Body and texture defects

•Melting Quality characteristics

•Color defects

•Shrinkage

Defects in ice creams

Flavoring System

Unnatural flavor - Caused by using flavors that are not typical of the

designated flavor i.e. wintergreen flavor on vanilla ice cream. esp. vanillin

Egg: Caused by using too much egg in an ice cream that is not specified as a

custard ice cream - resembles French vanilla ice cream .


Processing:

Cooked: Caused by using milk products heated to too high a temperature or

by using excessively high temperatures in mix pasteurization. It can dissipate

with time, the same as cooked defect in fluid milk. Sulfhydryl flavor: Caramel-

like, scalded milk, oatmeal-like.

Dairy Ingredients

High Acid: Use of dairy products with high acidity (usually due to bacterial

spoilage) or holding mix too long and at too high a temperature before freezing.

Acid/sour flavours are more rare these days due to the growth of proteolytic

psychrotrophs during storage at elevated temperatures, rather than lactic acid

bacteria.

Salty: Ice cream too high in milk solids-not-fat. Too much salt may have been

added to the mix. High whey powder, or maybe salted butter used instead of

sweet butter.


Old Ingredient: Caused by the use of inferior dairy products in the preparation

of the mix. Powders made from poor milk or stored too long at elevated

temperature or butter made from poor cream will contribute to old ingredient

flavor. Unpleasant aftertaste.

Oxidized: Caused by oxidation of the fat or lipid material such as phospholipid,

similar to fluid milk oxidation. Induced by the presence of copper or iron in the

mix or from the milk itself. Mono-and-di-glyceride or Polysorbate 80 can also

oxidize. Various stages - cardboardy, metallic (also described as painty, fishy).

Rancid: Caused by rancidity (high level of free butyric acid from lipolysis) of

milk fat. May be due to use of rancid dairy products (pumping or excessive

foaming of raw milk or cream) or to insufficient heat before homogenization of

mix. See description of Lipolysis, especially the release of free butyric acid.


Coarse/Icy Texture: Due to the presence of ice crystals of such a size that

they are noticeable when the ice cream is eaten.

May be caused by:• Insufficient total solids (high water content).

• Insufficient protein.

• Insufficient stabilizer or poor stabilizer.

• Insufficient homogenizing pressure (due to its effect on fat structure formation).

• Insufficient aging of the mix (stabilizer hydration, also fat crystallization and

development of resulting fat structure).

• Slow freezing because of mechanical condition of freezer.

• Incorporation of air as large cells because of physical characteristics of mix or type of

freezer used.

• Slow hardening.

• Fluctuating storage room temperatures.

• Rehardening soft ice cream.

• Pumping ice cream too far from continuous freezer before hardening.

• Fluctuating temperatures during storage and distribution - the most likely cause! See

discussion of ice cream shelf life.


Crumbly Body: A flaky or snowy characteristic caused by:

• High overrun together with large air cells.

• Low stabilizer or emulsifier.

• Low total solids.

• Low protein.

Fluffy Texture: A spongy/marshmallowy characteristic caused by:

• Incorporation of large amount of air.


• Low stabilizer content.

Gummy Body: This defect is the opposite of Crumbly in that it imparts a pasty

or putty-like body. It is caused by:

• Too low an overrun.

• Too much stabilizer.

• Poor stabilizer.


Sandy texture: One of the most objectionable texture defects but easiest to

detect. It is caused by Lactose crystals, which do not dissolve readily and

produce a rough or gritty sensation in the mouth. This can be distinguished

from "iciness" because the lactose crystals do not melt in your mouth. This

defect can be prevented by many of the same factors that inhibit iciness:

• hardening the ice cream quickly

• maintaining low storage room temps.

• preventing temperature fluctuations...from manufacturer to consumer

Weak Body: Ice cream lacks "chewiness" and melts quickly into a watery

liquid. Gives impression of lacking richness. May be caused by:


• High overrun.

• Insufficient stabilizer.

Melting Quality Characteristics

1. Curdy Melt-Down: May be due to visible fat particles or due to coagulation of

the milk proteins so is affected by factors that influence fat destabilization or the

protein stability such as:

•High acidity (protein coagulation).

•Salt balance (protein coagulation).

•High homogenizing pressures (fat coagulation).

•Over-freezing in the freezer (fat coagulation).

2. Does not Melt: May be caused by:

•Over emulsification.

•Wrong emulsifier.

•High fat.

•Excessive fat clumping in the mix due to homogenization at too low a

temperature or single-stage homogenizer.

•Freezing to too low a temperature at freezer.

3. Wheying off: The salt balance, protein composition, and carrageenan addition

(or lack or it) all are factors.


Color DefectsColor Uneven: Applies usually to ice cream in which color has been used, but may be

noticed in vanilla ice cream under some circumstances.

Color Unnatural:

• Wrong shade of color used for flavored ice cream.

• Too much yellow coloring used in vanilla ice cream.

• Grayish color due to neutralization.

ShrinkageA very troublesome defect in ice cream since there appears to be no single cause or

remedy. Defect shows up in hardened ice cream and manifests itself in reduced volume of

ice cream in the container usually by pulling away from the top and/or sides of container.

Structurally, it is caused by a loss of spherical air bubbles and formation of continuous air

channels. Some factors believed associated with the defect are:

• Freezing and hardening at ultra low temperatures.

• Storage temperature. Both low and high appear to contribute.

• Excessive overruns.

• Pressure changes, for example, from altitude changes (lids popping when shipped to

high altitudes, shrinkage when returned to low altitudes).


References

• The Science of Ice cream, C.Clarke

• Ice cream, Rich Hartel and Douglas Goff

• Dairy Processing Handbook

Thank you

Presented by : Namratha Kollu

ice cream namratha kollu - agrihortico · 2019. 12. 10. · ice cream • ice cream, kulfi,...

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