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Food additives data book - wordpres

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Polysaccharides 670<br />

NAME: Calcium alginate<br />

CATEGORY: Polysaccharides<br />

FOOD USE: All food products/ Edible films/ Coatings<br />

SYNONYMS: CAS 9005-35-0/ E404/ Calcium alginate/ Alginic acid-calcium salt/ Calcium polymannuronate<br />

FORMULA: Variable, depending on ratio of mannuronic to guluronic acid, and the presence of other substituents<br />

MOLECULAR MASS: Variable<br />

ALTERNATIVE FORMS: Alginic acid; algin; calcium alginate; potassium alginate<br />

PROPERTIES AND APPEARANCE: White to yellow powders or hard flakes<br />

SOLUBILITY % AT VARIOUS Solubility in aqueous solution varies with differences in structure, molecular weight, pH and cations.<br />

TEMPERATURE/pH COMBINATIONS: Alginic acid (low pH) is insoluble in water, monovalent salts (sodium, potassium and ammonium) are<br />

also soluble, but divalent salts (including calcium) except magnesium are insoluble in water. Solubility<br />

declines with increasing molecular weight and increasing concentration. Viscosity is not affected in the<br />

pH 5 to 11 range, but increases at lower pHs (due to alginic acid formation).<br />

FUNCTION IN FOODS: Gelling agent; thickening agent; stabiliser; flocculant and bulking agent. It can be used to stabilise<br />

emulsions and to retard ice-crystal formation<br />

ALTERNATIVES: Carrageenans; gelatin; gellan; agar, xanthan; furcellaran (application-dependent)<br />

TECHNOLOGY OF USE IN FOODS: Alginates should be dispersed in cold deionised water and heated for 10 minutes at 80°C to hydrate<br />

the polysaccharide. A high shear mixer will aid dispersion, although prolonged shear of high<br />

molecular-weight polymers will reduce the viscosity. Calcium gels can be prepared by addition of<br />

alginate solutions to a calcium solution (e.g. maraschino cherries), addition of calcium to a<br />

hot solution of alginate and then cooling (gel is thermo-irreversible), or by diffusion. Gels can<br />

also be formed by lowering the pH (alginic acid), but this can be technically difficult. Ammonium<br />

alginate forms particularly viscous solutions.

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