DETERMINATION OF ALGINATE IN DAIRY PRODUCTS

Comprehensive study was made of the precipitability of several hydrocolloids and other related compounds by divalent cations and, specifically, of the optimum conditions for recovering alginate from milk and dairy products by precipitation as calcium, strontium, and manganese salts. In aqueous dispersion, these cations selectively precipitated alginate, pectinic acids, and pectic acid. Alginate was recovered from milk, chocolate milk, ice cream, cheese spreads, cream cheese spreads, and other products by predigesting the mixture with papain, clarifying the digest with Celite 535 and charcoal, filtering and converting any pectin, pectinic acid, and pectic acid to galacturonic acid by pectinmethylesterase (pectinesterase) and polygalacturonase. Then, calcium chloride was added to the filtrate. The calcium alginate precipitate was washed free of sugars, dispersed by sodium hexametaphosphate, and the amount of alginate in the dispersion determined by the phenol-sulfuric acid test. Recoveries obtained were 96-101% for water dispersions, 92-96% for milk, 90-95% for ice cream, and 85-95% for cheese products. © 1969, American Dairy Science Association. All rights reserved.