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ENLIGHTENED THINKERS

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Darwanian Evolution

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Reaction

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Equilibrium

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Gums and Stabilizers

Relative Ranking of Gums

Suspension Ability

Suspension Requires a Gelling Agent

Chocolate milk - carrageenan Salad dressing - Xanthan, Pectin Processed Fruits - Pectin

Gums with Useful Protein Reactivity

Pectin (pH< 4.6) Carrageenan (pH> 4.6)

Natural vs Not Natural

Not Natural

MC HPC CMC PGA LMA Pectin

Natural

HMP & LMP Carrageenan Tragacanth, Karaya Agar, Gelatin Na alginate, Guar, Tara Xanthan, Gellan Konjac, Arabic LBG

Gelling vs Thickening

Thickening

Guar LBG CMC PGA Arabic Tara Tragacanth Karaya Xanthan

Gelling

Pectin Carrageenan Gellan Agar Methyl Cellulose Na alginate Konjac Gelatin

Hydrocolloids Solubility in Various Temp.

Special cases

Konjac

Swell below 90 Soluble at temp. 90?>

Agar

Not soluble below temp. 70 and swell at 70 Soluble at temp. 90/>

Gelatin

Soluble in temp. above 25 and swell at 25

Soluble in all temp. about range 25-90/>

Guar Arabic Xanthan CMC Pectin *85-90% soluble in temp. 25

Solution Clarity

Guar Starch LBG Xanthan Polyproplyene Alginate Konjac Microcystalline cellulose

Good

Pectin Refined LBG

Cellulose Carrageenan Gellan Gum Arabic Gelatin Agar

Acid stability (pH<4.0)

Fair

Guar PGA MCC Gelatin Alginate Agar

Poor

Carrageenan Cellulose derivatives

Excellent

Pectin Xanthan Gellan LBG Tragacanth

Main Classes of Hydrocolloids

Microbial Gums

Xanthan Gums - polyssaccharides from the fermentation of CHO substrate with Xanthomonas campestris

Thickening, suspending and stabilizing effects Pseudoplastic - thin with shear and recover their initial viscosity when shearing stops - important for good flavour release, mouthfeel

~Completely soluble in cold water ~Viscosity - High viscosity at low concentration ~Stable to heat and pH - Remain unchanged across temp. range 0-100, pH 1-13

Extract from tubers

Konjac glucomannan

Extract from seaweeds

Alginate from brown seaweed (Laminaria hyperborea), made up of blocks of D-mannuronic acid (M-block) and L-guluronic acid(G-block)

Propylene glycol alginate (esterified form of alginate) stabilize emulsion e.g: mayonnaise/ low-fat mayonnaise

Thickener in beverages e.g: dry mix fruit drinks, gives fast hydration and mouthfeel

Stabilizing effect in frozen products e.g: ice cream to avoid crystallization, gives homogenous breakdown without whey separation

Properties *Ratio of M:G and MW of polymer determine the solution and gelling properties

Can form gel in cold water in the presence of Ca ions, *gel are thermoreversible

High G alginate forms strong, brittle gel with good heat stability

Carrageenan - from seaweed of the rhodophyta family, composed of linear galactan polyssaccharides that have a sulfate content of 15-40%

Type of Carrageenan

Lambda, repeating of D-Galactose-2-Sulphate and D-Galactose-2,6-Disulphate with 35% of sulphate content

Kappa, repeating unit is D-Galactose-4-Sulphate linked with 3,6-anhydrous-D-Galactose with 25% of sulphate content

Iota, repeating unit is D-Galctose-4-Sulphate linked with 6-anhydrous-D-Galactose-2-Sulphate with 32% of sulphate content

Gelation of Carrageenan

Kappa and iota carrageenan has the ability to form thermoreversible gels upon cooling of hot aqueous solution containing various cation

Lambda carrageenan do not gel because it structure does not allow double helices formation

Structure of kappa & iota allow the two molecules to form double-helices-like structure, a chain molecules in 3-D network, a gel

Cations are important. Calcium ions and potassium ions form bridges between adjacent double helices through an electrostatic binding in two adjacent sulphate groups so, it stabilize and strengthening the network.

Extract from seed

Guar gums - linear chain of mannose with single galactose units attached as side chains

Very stable from pH 4-10

More highly substituted than LBG *more soluble, hydrates fully in cold water giving high viscosity

Nongelling *mainly used as viscosity builder, stabilizers and water binder

Locust bean gums - from the seed of carob bean, seed of the leguminose Ceratonia siliqua (indigenous to Mediterranean countries)

Canned foods, sauces, desserts, beverages, ice cream, processed meat

Primary function: thickening, emulsion stabilizer, inhibit syneresis

Non-ionic, stable over pH range 3.5- 11.0

Does not form gel by itself *combined with xanthan gums to gel

Maximum viscosity develop when heated to 95 degree Celsius, then cooled

Insoluble in cold water *must be heated to dissolve

Galactomannan gums *made up of mannose and galactose, in ratio of 4:1

Extract from part of plants

Cellulose Derivatives - chemically modified cellulose through alkaline treatment that converts cellulose into an ether. E.g: carboxymethylcellulose (CMC), hydroxypropylmethylcellulose (HPMC)

Use in fried food to: create barrier to oils absorption, retard loss of moisture, improve adhesion of batter

Methylcellulose (MC) and HPMC gel when heated. It also returns to origial liquid viscosities when cooled

Very clear solution, Stable over pH 4-10

Pectin - from peel of citrus fruits/ apple pormace

Gelation of Pectin

HMP: gels at high solids, low pH HMP: DE increase, gelling ability increase LMP: forms gel with calcium ions, loses ability as DE increases

Type of Pectin

Low Methoxyl Pectin (LMP)

Application

Heat reversible *utilised in bakery jams, jellies for glazing purpose

Used in jams with soluble solids <55% *low calories jam, jellies preserves

Formation of Gel

"egg-box" model 1. chain segment with 14/> residues having a ribbon-like symmetry forms parallel-oriented aggregates. 2. Calcium ions fit into cavities in the structure. 3. Chelate bonds with Oxygen from both galacturonan chains formed by calcium ions are formed.

Wide pH range (1-7) *soluble solid can be up to 85%

Low solid content

Presence of Calcium ions

DE < 50%

Amidated LMP (ALMP) *very reactive calcium ions , assist gelation in low sugar food preparation; e.g: low-sugar jams and jellies

Conventional LMP *less reactive calcium ions than ALMP, used as thickening agent in yogurt fruit

High Methoxyl Pectin (HMP)

Structure

Excellent flavour release

Clear and transparent

Not heat reversible

Firm and short structure

Setting times from 1-3 mins to more than 1 hr

DE- 58-75%

Classified further into

slow set (DE as low as 58)

Suitable to very acid fruits *to avoid premature gelation

ultrarapid/ rapid set (DE as high as 77)

Used in jams with whole fruits *to ensure uniform distribution of fruits particles

Formation of gel

Effect of pH in gelation Rapid sey pectin will set at higher pH, higher temperature than slow set pectin High DE, less soluble solid, higher pH which gels can be formed

pH= About 2.8-3.8

Soluble solid content= About 55-85%

Derivatives from exudation/ sap/ trees

Gum Arabic/ gum acacia - sap exuded from various species of Acacia trees

Uses

Soft drink emulsion *As emulsifier and stabilizers

Foam in beer *promote stabilization

Encapsulation agent *to encapsulate visible flavour compounds

Used in confectionery products *to retard sugar crystallization, promote emulisification

Properties

Least viscous

Easily dissolve in hot/cold water *most soluble of all hydrocolloids, 55% solid conc. can be used

Food hydrocolloids - a range of polyssaccharides and protein, known as 'water soluble gums', 'gums', 'stabilisers'

Factors affecting GUMS

Side Chain

Distribution

Number

Type

Monosaccharides composition

Molecular weight

Structure of hydrocolloid

High MW polymer, long chain sugar units with branches. Branches will determine ionic or non-ionic gums

Degree of Polymerization (DP)

Lower DP - Low viscosity, faster to hydrate

Higher DP - High viscosity, slower to hydrate

Degree of Substitution (DS)

Lower DS - Slower to hydrate

Higher DS - Faster to hydtrate

Used less than 2% in food

Functions

Secondary

Film formation

Encapsulation

Crystallization contoller

Suspension of particulates

Emulsion stabilizers

Primary

Gelling/ Texturizing agents

Thickening agents