APPLIED TECHNOLOGY

Hydrocolloids - What Can They Do? How Are TheySelected?

J.E. Trudso

A1S Kobenhavns Pektinfabrik(The Copenhagen Pecti Factory Ltd.)

DK-4623, lille ShensvedDenmark

IntroductionThe purpose of this paper is to present practical.

applicable tools for people in product development;tools that will facilitate a screening and rough selectionof hydrocolloids as possible candidates for fulfilling tech­nological needs in processed food products.

Before these tools can be used, the technologicalneeds must have been defined, and this paper endswith examples of these.

Since this paper has intentionally been made as sim­ple as possible, not all aspects of, especially, the proper­ties of hydrocolloids are included. There are, indeed, anumber of exceptions ot the rules, but in this respect, itis suggested that the readers consult the vast volume ofmore scientific papers or some of the thorough reviews.For example, Glicksman, M., Food Hydrocolloids,Volumes I, 11, Ill. eRe Press, Inc., Boca Raton, FLorida. 1982,1983, 1984.

4. Food Applications (Table 4).

5. World ConsumptionGenerally, hydrocolloids show an increase in con­

sumption of 2 - 3% p.a., however, low methoxyl pectinand xanthan gum show stronger growth, whereas theconsumption of PGA is stagnant. LBG and gum arabicshow a fluctuating trend, which in the case of gumarabic is caused by political instability (Table 5).

6. ExampleAs a retrospective example of how the information

contained in this paper can be used, gelled milk des­serts (pudding, flans, custard) is selected. Table 6 lists thevarious needs that have occured over the time and thefulfillment of these (Table 6).

Linear

Branch-on-branch

Single branch

_1 __ ' __1_ .J _l_l_ J_.J _ Substituted linearI 1 I I I I I

I I I1-- I-T-

_____, J. __I I

I ---I lI 1---

I

-----r------L _

1. ClassificationHydrocolloids are water soluble polymers with the abil­

ity to thicken, or gel aqueous systems.They can be classified according to origin, isolation

method, function, texture, thermoreversibility, gelling time,or charge, where texture, thermoreversibility, and gell­ing time are classification methods more appropriate forgelling agents.

Table 1 lists a number of hydrocolloids classified inthese ways and it must be noted that the charge of pro­teins is dependant on the system-pH.

Basically, hydrocolloids show one of the structures pic­tured in Figure 1.

2. Characteristics (Table 2).

3. Properties (Table 3). Fig. 1. Hydrocolloid polymer structures.

Can. Inst. Food Sci. Technol. J. Vol. 21, No. 3, 1988 AT / 229

Table 1. Classification

Origin Isolation method Function

Hydrocolloid Animal Land Seaweed Micro- Ground Exe- Extract Gel!. Thickener Sfabilizerplants organisms plant date agent

mat.HM-pectin X X X X XLMC-pectin X X XLMA-pectin X X XCarrageenan X X X XAgar X X XAlginate X X X X XCMC X XGuar gum X X XLBG X X XXanfhan gum X X X XGellan gum X XGelatine X X XGum arabic X X X XCaseinate X XWhey protein X XSoy protein X X X

Table 1. (Confinued)

Texture Thermorev. Gell. Time Charge

Hydrocolloid Brittle Cohesive Spreadable Yes No Yes No 0 +HM-pectin X X X X XLMC-pectin X X X X X XLMA-pecfin X X X X X XCarrageenan X X X X X XAgar X X X XAlginate X X X X XCMC XGuar Gum XLBG XXanthan gum X X X XGellan gum X X X XGelatine X X X X X XGum arabic XCaseinate X X X X X XWhey protein X X X X X XSoy protein X X X X X X

Table 2. Characteristics and examples.

Structure Characteristics

Linear Usually not more than two copolymerized sugar units. High vis­cosity. Unstable solutions. Difficult to dissolve. Risk of precipita­tion after dissolution (gelation).

Examples

Cellulose, Amylose, pectin, car­rageenan, alginate, agar

Single branch

Substitutedlinear

Branch-on-branch

230/ AT

Sugar units condensed with carbon groups other than C-1 or C4. Dextran

Numerous short branches often consisting of only one sugar unit Locust bean gum, guar gumin length.

Side chains on side chains. Amylopectin, gum arabic,More stable and less viscous than linear.Typically, two or more types of sugar make up the polysaccha­ride.Excellent adhesive properties.

J. Inst. Can. Sci. Technol. Aliment. Vo!. 21, No. 3, 1988

Table 3.1. Properties. (Continued on 3.2 and 3.3)Property High methoxyl pectin Low methoxyl pectin Kappa carrageenan Iota carrageenan Lambda carrageenanSolubility in water Sol. cold and hot Sol. cold and hot Sol. above 70°C, Na+ and Sol above 70°C. Na+ and Sol. cold and hot

NH4 + Sol. cold NH4 +. Sol. cold. K+andCa2+ swell cold to thix-otropic dispersions

Solubility in milk Sol. cold and hot Sol. hot Sol. above 70°C Sol. above 70°C Sol. hot. Swells cold

Solubility in salt solutions Insoluble Insoluble Insoluble Sol. hot Sol. hot

Solubility in sugar solu- Sol. hot Sol. hot Sol. hot Insoluble Sol. hottions

Solubility in ethanol Insol. above 20% Insol. above 20% Insol. above 20% Insol. above 20% Insol. above 20%

Other factors influencing Increases with decreasing Increases with decreasing Increases with decreasing Increases with decreasing Increases with decreasingsolubility MW, increasing random- sugar and Ca2+ Na+,K+ and, CO2 Na+, K+, and Ca2+ Na+, K+. and Ca2+

ness of COOH, decreasingsugar and Ca2+

Solution viscosity Low Low Low Medium High

Optimum pH range 2.5-4.0 2.5-5-5 4-10 4-10 4-10pka - 3.3

Optimum soluble solids 55-80% 30-80% 0-40% 0-20% 0-80%range

Gelation conditions pH below 4 and sol. solids Presence of Ca2+ 10- Presence of K+, No + or Presence of K+, No+ or Non-gelling55-80% 70 mg/g pectin. Temp. Ca2+. Temp. below setting Ca2+. Temp. below setting

below setting temp. temp. temp.

Gel characteristics:Texture Cohesive, no syneresis Cohesive to brittle. Brittle- Strong, brittle. Brittleness Soft, cohesive, thixotropic. Non-gelling

thermoirreversible ness increases with increases with increasing Thermoreversible Thix-increasing Ca2+ and K+ and Ca2+ and otropy is lost with additiondecreasing sugar. Ther- decreasing LBG. Ther- of LBGmoreversible moreversible

Setting temp. Increases with increasing Increases with decreasing Increases with increasing Increases with increasing Non-gellingDE, decreasing pH and DE, increasing DA, K+, Na+· Ca2+, and sugar K+, Na+, Ca2+, sugar,increasing sugar increasing Ca2+ and and LBG

increasing sugar.

Gel Strength Increases with increasing Increases with increasing Increases with increasing Increases with increasing Non-gellingconcentration and MW concentration and Ca2+ concentration, K+· Ca2+, concentration, K+. Na+,

and LBG and Ca2+

Effect on milk at neutral Precipitation Gelation Ionic interaction. Ionic interaction. Ionic interaction.pH Increased gel strength Increased gel strength Increased viscosity

Effect on milk and other Adsorption to casein parti- None Precipitation below iso-pH Precipitation below iso-pH Precipitation below iso-pHproteins at acid pH cles below pH - 4.2.

Adsorption to soy proteinparticles below pH - 4.8

Incompatibility Water soluble alcohols, Water soluble alcohols, Water soluble alcohols, Water soluble alcohols, Water soluble alcohols,ketones, heavy metals, ketones ketones, quaternary deter- ketones. quaternary deter- ketones, quaternary deter-quaternary detergents, gents, cationic macro- gents, cationic macro- gents, cationic macro-cationic macromolecules molecules molecules molecules

Table 3.2. (Continued trom 3.1)

Property Agar-agar Alginate Propylene glycol alg. Cellulose gum Locust bean gumIV Solubility in water Sol. above 90°C K+, Na+, NH4 + Sol. cold Sol. cold and hot Sol. cold and hot Sol. above 85°CwIV and hot Ca2+ Insol. at"- neutra pH;p....,

Sol. above 90°C Insol. Na+ swells in boiling Sol. cold and hot Insoluble Sol. above 85°CSolubility in milkmilk. Sol. with sequester-ing agents

Solubility in salt solutions Sol. above 90°C Insoluble Insoluble Insol. High OS types sol. Sol. above 85°C

Solubility in sugar solu-tions Sol. above 90°C Sol. hot Sol. cold and hot Sol. cold and hot Sol. above 85°C

Solubility in ethanol Insol. above 20% Insol. above 40% Insol. above 40% Insol. above 30% Insol. above 20%

Other tactors intluencing Increases with decreasing Increases with decreasingsolubility COOH, increasing pH, MW, increasing pH,

decreasing Ca2+ increasing divalentcations

Solution viscosity Low Low above pH - 5.5 High High High up to 85°CHigh below pH - 5.5

Optimum pH range 2.5-10 2.8-10, 2.8-10 3-10 4-10pka - 3.4-4.4 pka - 4.2-4.4

Optimum soluble solidsrange 0-80% 0-80% 0-80% 0-80% 0-80%

Gelation conditions Temperature below pH below 4 or presence ot non-gelling Non-gelling (gelation may Non-gelling32-39%C Ca2+ 20-70 mg/g alg. occur with trivalent

cations)Gel characteristics:

Texture Strong, brittle. Thermoversi- Acid gels soli, cohesive Non-gelling Non-gelling Non-gellingble. Brittleness increases and thixotropic. Calciumwith increasing sugar gels strong, brittle.

Thermo-irreversible;-.

~ Setting temp. Constant Non-existent Non-gelling Non-gelling Non-gelling

Q Gel Strength Increases with increasing Increases with increasing Non-gelling Non-gelling Non-gelling~

~ concentration, increasing concentration, Ca2+ and

;;isugar and increasing pH decreasing pH down to

~ 3.6~

"-:>. Effect on milk at neutral

r pH None None. Insoluble None Precipitation Separation

< Effect on milk and other None None None Adsorption to casein parti- None2-

proteins at acid pH cles below pH - 4.6.'"z

Adsorption to soy protein0 particles below pH - 5.0.w

~ Incompatibility Water soluble alcohols, Water soluble alcohols, Water soluble alcohols, Water soluble alcohols, Water soluble alcohols,ketones ketones, milk, gum arabic ketones ketones, quaternary deter- ketones

gents, cationic macro-molecules

Q Table 3.3 (Continued from 3.2)~

? Property Guar gum Xanthan gum Gelatine Gum arabic

"' Solubility in water Sol. cold and hot;SO Sol. cold and hot Sol. above 40°C Sol. cold and hot'"'"~ Solubility in milk Sol. cold and hot Sol. cold and hot Sol. above 40°C Sol. cold and hot

~ Solubility in salt solutions Sol. cold and hot Sol. cold and hot Sol. above 40°C Sol. cold and hot:;;."se-c- Solubility in sugar solu- Sol. cold and hot Sol. cold and hot Sol. above 40°C Sol. hot< tions2-N

Solubility in ethanol Insol. above 20% Insol. above 50% Insol. above 20% Insol. above 60%z0

.w Other factors influencing Increases with decreasing Increases with increasing;;; solubility MW pH up to 6g:;

Solution viscosity High cold. Low hot High below 100°C Low Low

Optimum pH range 4-10 1-13 4.5-10 2-10iso-pH - 4.8-5.2 (Iimed)iso-pH - 6.0-9.5 (acid)

Optimum soluble solids 0-80% 0.80% 0.80% 0.80%range

Gelation conditions Non-gelling Presence of LBG, tara Temp. below setting temp. Non-gellinggum, cassia gum. Temp.below setting temp.

Gel characteristics:Texture Non-gelling Cohesive, gummy, ther- Soft to strong, cohesive, Non-gelling

moreversible. Guar makes gummy. Thermoreversibletexture of xanthan/LBG gelmore brittle

Setting temp. Non-gelling Constant Increases with increasing Non-gellingMW and maturingtemperature

Gel Strength Non-gelling Increasing with increasing Increases with increasing Non-gellingconcentration concentration and

decreasing salt

Effect on milk at neutral Separation None None NonepH

Effect on milk and other None Precipitation below iso-pH None Noneproteins at acid pH

;I> Incompatibility Water soluble alcohols, Water soluble alcohols, Water soluble alcohols, Water soluble alcohols,.., ketones ketones, gum arable ketones, anionic macro- ketones, alg., gelatine, xan-"- below pH - 5 molecules below iso-pH, than gumN gum arabic below iso-phww

Table 4. Food Applications.

Hydrocolloid Food Function Concentration-%

Pectin Jams, jellies, preserves Gelation, thickening 0.1-1.0Bakery fillings, glazings Gelation, thickening 0.5-1.5Fruit preparations Thickening, stabilization 0.1-1.0Fruit beverages, sauces Thickening, stabilization 0.01-0.5Confectionery Gelation, thickening 0.5-2.5Dairy products Stabilizati, gelation 0.1-1.0

Carrageenan Ice cream Stabilization 0.01-0.03Chocolate milk Stabilization 0.01-0.03Flans and puddings Gelation, thickening 0.1-0.5liquid coffee whitener Thickening 0.1-0.2Low calorie jams Gelation, thickening 0.S-1.2Dessert gels Gelation 0.6-1.1Tart glaZing Gelation 0.S-1.0Meat products Gelation, waterbinding 0.3-0.5Pimiento paste Gelation 1.5-3.0Salad dressing Stabilization 0.3-0.6

Agar-agar lcings Gelation 0.1-0.3Confectionery Gelation 0.3-1.SMeat products Gelation 0.5-2.0Dairy products Gelation 0.05-0.9

Alginate Ice cream Stabilization 0.1-0.5Icings Gelation 0.1-0.5Toppings Gelation 0.3-0.5Salad dressings Stabilization 0.2-0.5Beer Stabilization 0.004-0.00SFruit drinks Stabilization 0.1-0.3Restructured foods Gelation 0.6-1.0Simulated fruit Gelation 0.S-1.0

CMC Ice cream Stabilization, thickening 0.1-0.3Ripples Thickening 0.1-0.4Sour milk Stabilization 0.1-0.2Cake mixes Moisture retention 0.2-0.4lcings Thickening, waterbinding 0.1-0.2Batters Thickening, stabilizaton 0.2-0.4Dry-mix beverages Thickening 0.1-0.3Syrups Thickening 0.2-0.6

LBG Ice cream Stabilization 0.2-0.3Cream cheese Thickening, moisture control 0.3-0.6Dessert gels Gelation, water retention

(together with carrageenan) 0.3-0.6

Guar gum Ice cream Stabilizatin 0.2-0.3Cottage cheese Thickening, 0.3-0.6Processed cheese Moisture retention 0.2-0.4Cake mixes Thickening 0.1-0.2

Xanthan gum Bakery jellies Gelation, thickening 0.1-0.3Fruit drinks Pulp suspension 0.02-0.06Cream cheese Gelation 0.1-0.2Baked goods Moisture retention 0.1-0.2Dressings Stabilization 0.2-0.3

Gelatine Yoghurt Gelation 0.3-1.0Dessert gels Gelation 4-6Confectionery Gelation 3-10Meat products Gelation 1-5Mousses Stabilization 1-3Minarine Stabilization 1-3

Gum arabic Flavour fixation Encapsulation SO-90Confectionery Stabilization, gelation 10-60Flavour emulsions Stabilizafion, emulsification 10-30

234/ AT 1. Ins£. Can. Sci. Techno/. Alimenr. Va!. 21, No. 3, 1988

Table 5. World consumption of food and pet food.

Hydrocolloid Consumption, 1986, t TrendHigh methoxyl pectin 12,000Low methoxyl pectin 5,000Carrageenan 14,000Agar-agar 6,000Alginate 6,000Propylene glycol alg. 2,000CMC 7,000LBG 6,000Guar gum 16,000Xanthan gum 4,000Gelatine 40,000Gum arabic 20,000

Increasing 2-3% p.a.Increasing 7-8% p.a.Increasing 2-3% p.a.Increasing 2-3% p.a.Increasing 2-3% p.a.Increasing 0.1% p.a.Increasing 2-3% p.a.FluctuatingIncreasing 2-3% p.a.Increasing 5-6% p.a.Increasing 1-2% p.a.Fluctuating

Table 6.

Problems

Retrogradation (linear)Needs preparationHeavy

Solution

Milk pudding gellified with amylose

Needs---------------------------------------

After dinner dessert made at home

Pudding with no retrogradation (crack­ing) made at home

Introduction of waxy starches andmodified starches (branched)

Needs preparationHeavy

Lighter pudding with no retrograda­tion made at home

Substitution of part or of all starch withcarrageenan, agar-agar, gelatine.(soluble in milk, gelling agents, low useconcentration).

Needs preparation.

More convenience. Instant puddings with carrageenan,alginate, xanthan gum,

Taste of polyphosphates, texture not asgelled as the original. Still some prepa­ration.

Convenience, better taste andimproved texture.

Industrially produced, pasteurizedpuddings with carrageenan, gelatine(Soluble at pasteurizing temperature,gelling agents).

Shelf life.

Convenience, improved shelf life. Sterilized puddings with carrageenan,agar-agar, gelatine. (Soluble at steriliz­ing temperature, gelling agents).

Increased competition,

Varieties.

Varieties with shorter production time.

Multi-layer desserts with carrageenan,gelatine, agar-agar.

Cold filling using carrageenan (thix­otropy)

Long processing time. Each layer mustbe cooled before addition of nextlayer. Gelatine further requires time forgelation.

Boundary problems when combiningacid water gel with neutral milk gel.(Carrageenan precipitates milk pro­tein).

Varieties with no boundary problems. SUbstituting carrageenan in milk gelwith low methoxyl pectin (slow settingvia diffusion of Ca2+).

Increased competition,

Varieties Sour milk desserts with agar-agar,gelatine, low methoxyl pectin.

Can. InSI. Food Sci. Technol. J. Vo\. 21, No. 3, 1988 AT / 235