Optimizing Dehydration Conditions of Cow's and Goat Milk Yogurt Powder

Abstract

Yogurt is one the importance the most common fermented dairy products widely consumed worldwide, mmostly studies are about in how to longer the yogurt shelf life, this study purposed to drying cow and goat milk yogurt by freeze dryer to provide alternative method don't have effect on yogurt compounds and lactic acid bacteria cell, and to identification the influence of stirring and time on yogurt powder compounds, the International Official Analytical Chemistry Association (AOAC) and the Indonesian National Standard (SNI) methods were used to analyze the chemical composition of yogurt powder, Cow’s and goat milks were mixed in rate 25:75 (v/v), inoculum with culture 15% (v/v) S. therophillus, L. acidophilus, L. burgaricus (1:1:1), and incubated at 46oC for 8h.Yogurt was dryed by freeze dryer at -73oC for 16, 19, and 22hours on 4, 5, and 3 batches with stirring respectively, The results obtained from this study that the best drying method of cow and goat yogurt treated by freeze dryer was19h., drying by freeze at batches with stirring have no significant effect on amount of bacteria cells, moreover, it is an excellent method to preserve the desirable microbiological properties in yogurt, and decreased the drying time and improving quality of final product.