EFFECT OF HEAT-TREATMENT ON THE NUTRITIONAL QUALITY OF MILK-PROTEINS

Milk, a food of high nutritional value, could have its quality reduced by an intense heat treatment, such as domestic boiling. The goal of t he present work was to verify the alteration in nutritional quality of milk proteins submitted to heat treatments through biological tests o f the food efficiency ratio, protein efficiency ratio, digestibility a nd in vitro liver protein synthesis. Pasteurization, domestic boiling of pasteurized milk and an Ultra High Temperature process were used as heat treatments. Weanling Holtzman male rats were used for biological determination and it was found that the treatments did not affect the biological value of milk proteins, except for liver protein synthesis when rats were fed a diet based on boiled pasteurized milk. Consideri ng the great advantage of heat for reducing microbiological contaminat ion, there is no reason to discourage the usual domestic heat treatmen t used in Brazil. (C) 1998 Elsevier Science Ltd. All rights reserved.