Gums and Stabilizers

Derived from the peel of citrus fruits (lemon, lime,orange), apple pomace, sugar beet, sunflower heads

Natural form is called
protopectin (insoluble)

Types of Pectin

High Methoxy Pectin (HMP)

Commercial high methoxy pectin: DE 58% to
75%

Setting times vary from 1-3 min to > 1 h

firm & short structure,
clear & transparent, excellent flavour
release

not heat reversible

gels at high solids & low pH

As DE increase, ability to form gel increase

Low Methoxy Pectin (LMP)

DE < 50% — two sub-groups:Conventional low methoxyl pectin (LMP),Amidated low methoxyl pectin (ALMP)

Form gels in the presence of Ca2+, with a low solids
content & wide pH range (1-7) [but soluble solids can
be up to 85%]

form gel with Ca but lose gelling ability asDE increase

LMP – less Ca2+ reactive than ALMP:used as a
thickening agent in yoghurt fruit

ALMP – very Ca2+ reactive : assist gelation in low sugar
fruit preparations, e.g. low-sugar jams & jellies

Typical Pectins Used

Jams, jellies & preserves

primary gelling agent in jams & jellies

Jam with suspended fruit particles requires rapidset
HM pectin

As stabiliser

in fruit juices fruit drink concentrates –
also to provide a “natural mouthfeel”

In fermented /directly acidified dairy products

Derived brown seaweedv(Laminaria hyperborea)

Made up of blocks of Dmannuronic
acid (M-blocks) & Lguluronicvacid (G-block)

ratio of M:G & the MW of polymer
determine the solution and gelling
properties of alginate

can form gel in cold water in the presence of Ca ion; the gel is thermo-irreversible.

Applications

excellent stabilizing effect in frozen products; e.g., used in ice cream to avoid crystallization,

In beverages, alginate act as a thickener & stabilizer – e.g., in dry mix fruit drinks, alginate gives fast hydration & mouthfeel.

Propylene (esterified glycol alginate form of alginate) has emulsification property – commonly used as stabilizer in emulsions like mayonnaise/low-fat mayonnaise.

Complex structure – polysaccharide
containing galactose, rhamnose,
arabinopyranose, arabinofuranose,
glucuronic acid.

Dissolve easily in hot/cold water

Least viscous & the most soluble of all
the hydrocolloids – up to 55% solid
concentration can be used

Uses

confectionery products – to retard sugar
crystallization & to promote emulsification

Encapsulation agent - to encapsulate volatile flavour compounds

Promote stabilization of foam in beer

Function as an emulsifier & stabilizer in
soft drink emulsion (30% of world supply)

highly refined extract of seaweed
from the rhodophyta family.

structure is composed of linear galactan
polysaccharides that have a sulfate content of 15-40%.

types of carrageenan

Kappa (-carrageenan)

Lambda (-carrageenan)

Iota (-carrageenan)

Gelation of Carrageenan

In a concentration as low as 0.5%, K- and I-carrageenan have the ability to form thermoreversible gelsvupon cooling of hot aqueous solutions containing various cations (e.g., K+); L-carrageenan does not form gel

Cations are important in carrageenan gelation. It
is believed that Ca2+ and K+ ions form bridges
between adjacent double helices through an
electrostatic binding to two adjacent sulfate
groups, thus stabilizing and strengthening the
network.

Come from seeds of the leguminose
Ceratonia siliqua (indigenous to
Mediterranean countries)

Galactomannan gums – made up of
mannose & galactose in a ratio of 4:1

Insoluble in cold water & must be heated
dissolve to max viscosity develop when
heated to ~95C, then cooled.

Does not form a gel by itself – but can gel
when combined with xanthan gum

Uses

LBG is non-ionic – stable over the pH range of 3.5 to 11.0

Primary functions: thickening, stabilization of emulsions, inhibition of syneresis

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

A linear chain of mannose with single galactose units attached as side chains

More highly substituted than LBG –
more soluble & hydrates fully in cold
water giving high viscosity

Nongelling – used primarily as a viscosity builder, stabilizer water binder

Very stable from pH 4 -10.

Polysaccharides produced from fermentation of CHO substrate with Xanthomonas campestris

Cellulosic backbone with trisaccharide
branches attached to every other
glucose unit in the main chain

Completely soluble in cold water and hot water produce high viscosity at low conc.

Excellent stability to heat & pH

Viscosity remain unchanged across the
temp range of 0 – 100 C & pH 1 – 13

Pseudoplastic – thin with shear recover their initial viscosity when shearing stops – important for good flavour release, mouthfeel.

Use for thickening, suspending and stabilizing effects

Food Hydrocolloids

A range of polyssacharides and proteins also known as 'water-soluble gum', 'stabilizers' , 'gums'

Functions

Primary Functions

Thickening agents

Gelling or texturizing agents

Secondary Functions

Stabilisation of emulsions

Suspension of particulates

Control of Crystallization

Encapsulation

Formation of Film

Thermoreversible Gelling Agents

Gel formed on heating or cooling and
the process is reversible

Examples: Gelatin, agar, -
carrageenan, -carrageenan, LM
pectin, gellan gum, methyl cellulose,
HPMC.

Thermally Irreversible Gelling Agents

Examples: alginate, starch, konjac,
HM pectin

Some hydrocolloids form gel on
heating/cooling; some require the
presence of cations

Others will form gel under acidic
pH + high sugar concentration,
some require pH and alkaline pH.

High MW polymers consisting long chain sugar units with substituent protruding from the main chain

Substituent will determine whether
the gums are non-ionic or ionic (there
are no cationic food gums)

Molecular Weight

Monosaccharide Composition

Type of Side Chains

Number of Side Chains

Distribution of Side Chains

Derivatives from exudation or sap of
trees

Extract from seed

Extract from seaweeds

Microbial gums

Extract from tubers

Extract from plant parts

Gum Arabic

Acacia Senegal L

Carragenan

Seaweed

Locust Bean Gum (LBG)

Seed of Carob Bean

Konjac Glucomannan

Armophophallus konjac, K. Koch tuber

Pectin

peel of citrus fruits (lemon,
lime, orange) or apple pomace

Examples: carboxymethylcellulose
(CMC), hydroxypropylmethylcellulose
(HPMC)

Very clear solution & stable over pH 4
to 10

Use for thickening, suspending,
stabilizing & modify flow characteristics

Methylcellulose (MC) & HPMC gel when
heated & return to their original liquid
viscosities when cooled

Use in fried foods in which they create
a barrier to oil absorption, retard loss of
moisture & improve adhesion of batter