Food Additive
Tue,6 Maret 2012
hydrocolloid
Refers to a range of polysaccharides and
proteins that are nowadays widely used in a variety of industrial sectors to perform a
number of functions including thickening and gelling aqueous solutions, stabilising foams, emulsions and dispersions, inhibiting ice and sugar crystal formation and the controlled
release of flavours, etc
hydrocolloids and sources of material
Tree (selulosa), tree exudates (gum arabic, gum karaya,gum ghatti, gum tracanth), plants (starch, pectin, selulosa) seeds (guar gum, locust bean
gum, tara gum, tamarind gum), tuber (konjac mannan)
Red seaweed (agar, karagenan), brown seaweed (alginate)
Mikrobial (xanthan gum, curdlan, dextran, gellan gum, selulosa)
Animals (gelatin, caseinate, whey protein, chitosan)
Fungsi hydrocolloid
Thickener (CMC, hydroxypropyl cellulose, methyl cellulose, microcrystalline cellulose, guar gum,
karaya gum, locust bean gum, starch, tragacanth, xanthan gum)
Gelling agent (agar, alginate, carrageenan, PES, methyl cellulose, gelatin, pectin)
Emuslifier (methyl cellulose, arabic gum, hydroxypropyl cellulose)
Regulatory aspects
International
European system
Other trade blocks (FCC, Japanese system)
International numbering system for food additives (INS)
Main hydrocolloid thickeners
Xanthan gum Very high low-shear viscosity (yield stress), highly shear thinning, maintains viscosity in the presence of electrolyte, over a broad pH range and at high
temperatures.
Carboxymethyl celluloseHigh viscosity but reduced by the addition of electrolyte and at low pH.
Methyl cellulose and hydroxypropyl methyl
celluloseViscosity increases with temperature (gelation
may occur) not influenced by the addition of electrolytes or pH.
Galactomannans (guar and locust bean gum)Very high low- shear viscosity and strongly shear thinning. Not influenced by the presence of electrolyte but can degrade and lose
viscosity at high and low pH and when subjected to high temperatures.
Thermoreversible gelling agents
Gelatin: gel formed on cooling. Molecules undergo a coil-helix transition followed by aggregation of helices.
Agar: gel formed on cooling. Molecules undergo a coil- helix transition followed by aggregation of helices.
Kappa Carrageenan: gel formed on cooling in the presence of salts notably potassium salts. Molecules undergo a coil- helix transition followed by
aggregation of helices.
Iota Carrageenan: gel formed on cooling in the presence of salts. Molecules undergo a coil-helix transition followed by aggregation of helices.
Pectin: gels formed in the presence of divalent cations, notably calcium at low pH (3–4.5). Molecules
crosslinked by the cations. The low pH reduces intermolecular electrostatic repulsions.
Gellan gum: gels formed on cooling in the
presence of salts. Molecules undergo a coil-helix transition followed by aggregation of helices.
Methyl cellulose and hydroxypropyl methyl cellulose: gels formed on heating. Molecules associate on heating due to hydrophobic
interaction of methyl groups.
Xanthan gum and locust bean gum or konjac mannan: gels formed on cooling mixtures.
Xanthan and polymannan chains associate following the xanthan coil-helix transition.
Thermally irreversible gelling agents
Alginate: gels formed on the addition of
polyvalent cations notably calcium or at low pH 4.
Molecules crosslinked by the polyvalent ions.
High methoxyl (HM) pectin: gels formed at high soluble solids (e.g. 50% sugar) content at low pH 3.5. The high sugar content and low pH reduce electrostatic repulsions between chains. Chain association also encouraged by reduced water activity.
Konjac mannan: gels formed on addition of alkali.
Alkali removes acetyl groups along the polymer chain and chain association occurs.
Locust bean gum: gels formed after freezing.
Galactose deficient regions associate.
Advantages of hydrocolloids
Cheap prices
Not influenced on taste
Giving better rheological properties of the products
Hydrocolloids fibers has many purposes
Agar
Agar is defined as a strongly gelling hydrocolloid from marine algae.
Agar is a polysaccharide that accumulates in the cell walls of agarophyte algae. It is embedded in a structure of fibres of crystallised cellulose, constituting its polysaccharide
reserve.
Its main structure is chemically characterised by repetitive units of D-galactose and 3–6,anhydro- L-galactose, with
few variations, and a low content of sulfate esters.
Employed more than 300 years ago
Use mainly of their colloidal properties
Agar is a polysaccharide that accumulates in the cell walls of agarophyte algae. It is embedded in a structure of fibres of crystallised cellulose, constituting its polysaccharide
reserve.
Applications of Agar
Food application (Gelidium, Gracillaria, Pterocladia, Gelidiella)
Insect culture media formulation
Vegetable culture media formulation
MO culture media formulation
Health Industry
Starch
starch, an anhydroglucose polymer, member of the ‘polysaccharide’ group of polymers. It is laid down as insoluble, compact and
microscopic semi-crystalline granules of size
1– 100μm.
Apps
Baked goods
Batters and breading
Beverage emulsions and flavour encapsulation
Confectionery
Dairy products
Fruit preparations
Gravies, soup, sauces
Mayonnaise and salad dressings
Meat products
Savoury snacks
Gelatin
Collagen, the basic raw material for gelatin production, is the major constituent of all white fibrous connective tissue occurring in animal bodies such as cartilage, sinews, the transparent sheaths surrounding muscles and muscle fibres, skin and ossein (the protein
matrix of bone)
Uses for food, medical, and photography
Carrageenan
Extracted from Rhodophyceae (E. cottoni, E.
spinosum, Chondrus crispus, Gigartina, Fucellaria)
Consists of iota, lambda, kappa
Uses for food, dairy application.
