Food additives data book - wordpres

Polysaccharides 662
NAME: Algin
CATEGORY: Polysaccharides
FOOD USE: All food products, edible films/ Coatings
SYNONYMS: CAS 9005-32-7/ E407/ Sodium alginate/ Sodium polymannuronate
FORMULA: Variable, depending on ratio of mannuronic to guluronic acid, and the presence of other substituents
MOLECULAR MASS: Variable
ALTERNATIVE FORMS: Alginic acid; ammonium alginate; calcium alginate; potassium alginate
PROPERTIES AND APPEARANCE: White to yellow powders or hard flakes
SOLUBILITY % AT VARIOUS Solubility in aqueous solution varies with differences in structure, molecular weight, pH and cations.
TEMPERATURE/pH COMBINATIONS: Alginic acid (low pH) is insoluble in water, monovalent salts (sodium, potassium and ammonium) are
also soluble but divalent salts (including calcium) except magnesium are insoluble in water. Solubility
declines with increasing molecular weight and increasing concentration. Viscosity is not affected in the
pH 5 to 11 range but increases at lower pHs (due to alginic acid formation)
FUNCTION IN FOODS: Gelling agent; thickening agent; stabiliser; flocculant and bulking agent. It can be used to stabilise
emulsions and to retard ice-crystal formation
ALTERNATIVES: Carrageenans; gelatin; gellan; agar; xanthan; furcellaran (application-dependent)
TECHNOLOGY OF USE IN FOODS: Alginates should be dispersed in cold deionised water and heated for 10 minutes at 80°C to hydrate
the polysaccharide. A high shear mixer will aid dispersion, although prolonged shear of high
molecular-weight polymers will reduce the viscosity. Calcium gels can be prepared by addition of
alginate solutions to a calcium solution (e.g. maraschino cherries), addition of calcium to a
hot solution of alginate and then cooling (gel is thermo-irreversible), or by diffusion. Gels can
also be formed by lowering the pH (alginic acid), but this can be technically difficult.