Recovery and Nutritional Evaluation of Proteinaceous Solids Separated from Whey by Coagulation with Chitosan

Abstract

Chitosan, a cationic carbohydrate polymer manufactured from chitin in shrimp and crab wastes, coagulated suspended solids in cheese whey as effectively or more so than 10 commercial synthetic polymers. Concentrations of suspended solids after settling were reduced over 90% by coagulation at pH 6.0 with a ratio of chitosan to suspended solids of 2.15% (1:46.5). The yield of coagulated solids was .apprx. 2270 mg/l. The approximate composition of the coagulated solids after freeze drying was 73% protein, 6% lactose, 10% ash and 7% moisture. Without the aid of a coagulating agent, settling for 1 or 3 h reduced suspended solids by only 34% and 49%, respectively. Rat feeding studies showed no significant differences in the protein efficiency ratio of casein, coagulated whey solids containing chitosan and whey solids containing no polymer. These results provide evidence of utility for coagulated whey solids as a protein supplement.