Vitamin A and Haylike Flavour in Nonfat Dry Milk and Pasteurized Low Fat Milks

Abstract

A market survey indicated that 27% of nonfat dry milk samples had vitamin A levels less than the accepted minimum. As the vitamin A levels decreased during storage, the incidence of haylike flavour increased. For pasteurized skim milk, 39% of the samples had vitamin A levels less than the accepted minimum and 22% exhibited slight haylike flavour on or before their expiry date. Dry blending vitamin A beadlets with nonfat dry milk or addition of beadlets at the agglomeration chamber during instantization of nonfat dry milk were the best fortification methods for preventing vitamin A degradation and haylike flavour production. Fortification of nonfat dry milk with vitamin A dissolved in skim milk and butter oil was unsatisfactory. Ascorbic acid acted as an antioxidant in skim milk and prevented degradation of vitamin A during storage. Evacuating fluid skim milk, or flushing it with nitrogen, had virtually no effect on preventing the degradation of vitamin A.