Functions of Gums in Food Systems

Water binding

Viscosity building

Gelation

Suspension

Emulsions stabilization

Foam stabilization

Encapsulation

Binder

Fat Replacement

Functions in foods are related to interactions with other food components.

Gums interact with:

All functions of gums require that the gums be hydrated.

Failure to hydrate gums properly is the leading cause of problems in foods containing gums.

Hydration of Gums

Linear, uncharged polysaccharide molecules are held tightly together by hydrogen bonds. Substantial inputs of energy are required in order to make these function properly.

Amylose crystalline structure requires substantial input of heat before gelatinization occurs.

Locust Bean Gum (has some branches) requires heating to fully develop viscosity

Guar Gum ( 2x as many branches) swells in cold water

Introduction of branches and/or charges into the chain limit the amount of hydrogen bonding that can take place between polysaccharide molecules and thus increase the interaction with water and make gums more easy to hydrate.

Carrageenan - charge of sulfates

Xanthan - Charge on carboxyl + branches

Guar - increased branches

Gums and proteins

May affect protein stability by:

Electrostatic interaction - negatively charged hydrocolloids may interact with positively charged groups on proteins. Interactions depend on:

pH

pK of ionizable group

Ionic strength

Ratio of protein to gum

Interference with calcium binding - Protect calcium sensitive proteins e.g.. carrageenan

Competing for water - hydrocolloids may cause proteins to precipitate by limiting the water available to hydrate the protein.

Gums and Fats

Only a few gums show affinity for fat. Gum Arabic, hydroxypropyl cellulose, propylene glycol alginate and gum tragacanth have a little affinity for fat.

Stabilization of emulsions, foams, etc. is dependent upon interactions with the protein on the surface and increases in viscosity of the continuous phase.

Gums which are complexed with other food components may not be able to exert their primary functions.

Unhydrated gums are non-functional in food systems.

Viscosity of gums

All are highly viscous except Gum Arabic

Viscosity is dependent upon hydration of the polysaccharide. Larger polymers generally give higher viscosity. Interactions with other polymers may dramatically affect viscosity.

Stability of Gums

Most gums are resistant to microbial degradation

Pectin is a notable exception

Commercial stabilizers almost always are 'standardized" with sugar and thus are readily fermented.

Depolymerization upon heating is common.

Classification of gums used in food products:

Non-ionic seed polysaccharides —

Guar, Locust Bean (Carob) Tamarind

Anionic exudate polysaccharides —

Arabic, Karaya, Tragacanth

Anionic seaweed polysaccharides —

Agar, Algin, Carrageenan

Microbial gums -

Xanthan, Gellan

Others -

Celluloses, Pectins

Classification of Polysaccharides Based on Structure

Neutral

Starch

Cellulose

Locust Bean Gum

Guar Gum

Carboxylated

Algin

Carboxymethylcellulose

Pectin

Xanthan

Sulfated

Carrageenan

Furcellaran

 

Guar Gum

Galactomannan (Mannose (1-4) + Galactose (1-6) every other Mannose

MW 220,000 ± 20,000

Particle size affects viscosity and hydration

Cold water swelling - Turbid solutions

Pseudoplastic - shear thinning

Hydration increased by heating

High water binding

High viscosity form - up to 100,000 CP

Low viscosity from - up to 10,000 CP

Modifies properties when used with

Carrageenan

Xanthan

Food uses

Ice cream (prevents ice crystal formation, slow meltdown, heat shock resistance)

Salad dressing (viscosity)

Cheese (improves spreading)

Guar Gum

Locust Bean Gum

Viscosity of 1% Guar Gum with various amounts of sugar

Locust Bean Gum

Galactomannan (D-Mannose (1-4) with Galactose (1-6) every 4th mannose

Molecular weight 330,000 ±30,000

Neutral - relatively unaffected by ions, pH.

Not soluble in cold water

Fully hydrated if heated 10 minutes at 80° C

Solutions are cloudy, off-white

Pseudoplastic - shear thinning, zero yield value

Modify properties of

Carrageenan

Xanthan Gum

Food uses similar to Guar Gum

Gum Arabic (Acacia)

Highly branched with b-Galactose backbone

Molecular weight 250,000 - 750,000

Water soluble, fat insoluble

Low viscosity gum

Viscosity affected by pH and salts

Food uses:

Stabilizer for flavor emulsions

Encapsulated flavors

Water binding

Inhibit sugar crystallization

Gum Tragacanth

Polymer of Galacturonic Acid + Galactose + Galactose + Arabinose + xylose

Two components

70% Bassorine - swelling

30% Tragacanth - cold water soluble

Acid stable

High viscosity (varies with grade) 600 -4,000 CP at 1%

High cost

Food uses include:

Salad dressing (emulsifier)

Pickle relish (Increases drained weight)

Milkshake (reduce calories, thickener)

Pulpy beverages (stabilize solids - enhanced by Gum Arabic)

Ice Cream (surface tension related)

Karaya

Introduced as a Tragacanth substitute

Molecular weight about 950,000

Acetylated Galacturonic acid + Rhamnose + Galactose

Swells in aqueous environments

Used as adhesive

Food Uses include:

Powdered doughnuts

French dressing

Ice pops (prevents ice crystals, binding of free water)

Cheese spread (improves spreading)

Ground meats

Meringues

With Gum Arabic as protective colloid

Agar

From seaweed

Galactan

Insoluble in cold water

1.5% gel doesn't melt below 85° C

Temperature reversible gels

Used for gels in confectionery

High temperature tolerant gels

Algin and Alginates

Polymers of Mannuronic and Galacturonic acids varying widely in ratios of the two acids

Viscosity of 1% solution ranges from 10 to 2,000 CP as a function of molecular weight and calcium ion content

Precipitates below pH 3.0

Degrades above pH 6.5

Forms gels with calcium ions - 0.5 to 1.0% calcium

Propylene glycol derivative improves stability to calcium and acid

Food functionality includes:

Water binding

Gelling

Emulsifying

Stabilizing

Propylene Glycol Alginate

Ester reduces

Precipitation at low pH

Interaction with calcium ions

Some interaction with fat

"Slimy" mouthfeel can substitute for fat

Good foam stabilizer

Alginate Gels

Extrude into calcium bath

Use sodium alginate with a sparingly soluble calcium salt

Regulate calcium availability by regulating pH

Too much calcium gives grainy gels

Too slow release gives weak gels

Carrageenan

Galactose backbone

Ester sulfate gives negative charge

Gels with potassium (Kappa)

Gels with calcium (Iota)

Non-gelling (Lambda)

Good stabilizer for milk proteins

Suspender for chocolate in milk

Milk gels with TSPP

Part of ice cream stabilizer mix

Water gels

Carrageenans

Kappa

Lambda

Iota

Protein - Carrageenan Interactions

Protein with a negative charge

Protein with a positive charge

Typical Dairy Applications of Carrageenan

Comparisons of carrageenans

Xanthan

Backbone same as cellulose (1-4 Glucose)

Trisaccharide side chain at 3 position of alternating glucose monomer units.

Acid groups are b-D-Glucuronic acid and pyruvic acid on 1/2 of terminal mannose units.

High degree of interaction between chains. Molecular weight about 15 million.

Cold and hot water soluble

High viscosity at low concentration

Strongly pseudoplastic

Independent of concentration and shear rate

1% solutions gel-like at rest, but pour readily

Properties affected by ions

Freeze stable

Retort unstable - improved by 0.1% NaCl.

Viscosity of Xanthan and Locust Bean Gums

Gellan

Produced by Pseudomonas elodea

Composed of 2 b-Glucose units + b-Glucuronic Acid + Rhamnose

Molecular Weight 1,000,000

Insoluble in cold water

Gels with heat and Calcium

Typical use level 0.1 - 0.35%

Hard Gels

More tender gels with added Locust Bean or Xanthan

Fluid Gels Sworn et al. 1995. Gellan gum fluid gels. Food Hydrocolloids 9, 265-271.

CMC Carboxymethyl cellulose

Not all CMC is the same

30 producers make over 300 types of CMC

Anhydroglucose polymer with 100 to 3,500 units (Degree of polymerization = DP)

Degree of carboxymethyl substitution ranges from 0.4 to 1.2 /unit Dilute solutions have pH about 7.0 with acid group ionized (free acid form at pH < 3.0)

CMC has broad food usage - limited in part by labeling requirements in some locations.

Interaction with milk solids

Viscosity and Structure

Effect of salts

Pectins Read both of these articles: A Primer on the Making of Jams, Jellies, & Preserves; Pectin: Chemistry, Functionality, & Applications

Unbranched polymers of 200 - 1,000 Galactose units, linked b 1-4 Glucosidic bonds

Degree of esterification controls setting rate

>50% High Ester Pectins (HM)

<50% Low Ester Pectins (LM)

70 - 85% = Rapid Set

44 - 65% = Slow Set

Calcium required to gel LM Pectins

Amidatied LM Pectins used to gel natural fruit preserves

High ester (HM) Pectins stabilize sour milk drinks - react with casein

Low ester (LM) Pectins used for milk gels

Effect of Esterification on Setting Rate on Cooling

Forms of Pectin

Pectic Enzymes

Links

Food Product Design Articles -These are short and sweet. Read all of them.

Formulating by Gum, Pectin and Gelatin June 2002

Designing Foods Using Gums 1993

Stabilizers 1993

Beverage Viscosity, Any Way You Like It! 2002

Salad Dressings and Sauces: Through Thick and Thin 2001

Beverage Stabilizers 2000

Consumption Construction: Gums & Starches Build Texture 1995

Gum Selection

Carrageenan

Exudate Gums (Arabic, Tragacanth, Karaya)
http://www.iscgums.com/gum.htm

Excellent Pectin powerpoint presentation
http://www.cpkelco.com/Ptalk/ptalk.htm

Guar

Kelco

ISP Alginates

Degussa

FMC

Food Hydrocolloids (Journal available online only to OSU students)