Ascorbic acid content of milk and the effects of processing and storage on its losses [Egypt]
1985
Khader, A.E. (Monoufeyah Univ., Shebin El-Kom (Egypt). Faculty of Agriculture) | Farag, S.I.
Ascorbic acid content in milk was closely related to the heat treatment and storage conditions to which the product was subjected. Results optained indicated that human milk had the highest ascorbic acid content followed by ewe's, buffalo's, cow's and goat's milk. Ascorbic acid content of buffalo's milk decreased by 11.69% and 20.30% by heating at 62C for 30 min, 72C for 15 sec., and just boiling respectively. In cow's milk corresponding losses were 12.4%, 17.8% and 22.5%. Ascorbic acid content of heated buffalo's milk was reduced by 14-23%, 26-31% and 33-39% when stored for one, two and three days in refrigerator respectively. Corresponding losses were 15-24%, 26.3-30% and 34-37% for cow's milk. Storage at -20C/2 wk. decreased ascorbic acid by 10% and 4-7.5% in raw and pasteurized or boiled buffalo's milk respectively, while corresponding losses were 11.1% and 4.6-6.1% in cow's milk. The decreases of ascorbic acid were lower by about 44-46% and 40-44% for cow's and buffalo's milk respectively when milk enriched with sodium ascorbate than ascorbic acid used. The amount of the sodium ascorbate in vitaminized milk should be increased from 10 to 15 mg/100 g to compensate loss on heat treatment or boiling.
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