) I( بهبود كيفيت بستني كم چرب به كمك هيدروليز نسبي پروتيينهاي مخلوط بستني با كيموزين

Improving the Quality of Low-Fat Ice Cream By Hydrolyzing of Casein Micelles with Chymosin

Low-fat ice cream bears less than 5% fat in its composition. Much work has been done to produce either low or non-fat ice cream. Partial hydrolysis of casein micelles by chymosin employment can improve both the body and texture of ice cream. The purpose in this research was to improve the quality of low-fat ice cream through chymosin. Low-fat (2%) ice cream was prepared from mixes that were subjected to limited chymosin proteolysis. The mix was treated with either 0.75 or 0.95 1MCU of chymosin per kilogram of mix for either 15 or 30 min at 60°C. Chymosin has originally been produced from fungi and is nowadays available in market. Having the mix held at 63.3°C for 30 min after processing inactivated chymosin. Treated mixes were aged for 12 hr at 4°C and the ice cream was produced (95-100% overrun) using conventional techniques. Viscosity, surface tension, hardness and melting rate were evaluated, data analysis being done based on randomized complete block design (RCBD). Following chymosin treatment, viscosities as well as hardness were significantly increased but surface tension and melting rate decreased. The related changes in physico-chemical properties were observed to improve the quality of final product.