Fortification of milk with microencapsulated vitamin C and its thermal stability.

摘要

Stability of microencapsulated vitamin C in fortified buffalo milk during pasteurization and sterilization was studied. Liposomes containing encapsulated ascorbic acid were prepared by dehydration/rehydration process using egg phosphatidylcholine together with cholesterol and DL- alpha -tocopherol. The diameter of these liposomes was found to be in the range of 200-1000 nm and the efficiency of vitamin C encapsulation was found to be 59+or-4.89%. The average total vitamin C contents in unfortified raw, pasteurized and sterilized buffalo milk samples were 23.47, 20.09 and 11.34 mg/litre, while in milk samples fortified with encapsulated ascorbic acid were 366.71, 345.80 and 210.74, and for milk samples fortified with non-encapsulated ascorbic acid were 364.84, 322.37 and 203.21 mg/litre, respectively. Microencapsulation provided some protection to ascorbic acid in fortified milk at pasteurization temperature (63 degrees C for 30 min), however, at higher temperature as used for sterilization (121 degrees C for 15 min), microencapsulation was not of much use..