Effect of fermentation temperature and culture concentration on microbial and physicochemical properties of cow and goat milk yogurt

Abstract

This present study aimed to assess the effect of fermentation temperature and culture concentration on LAB growth, physical and chemical properties of fermenting cow and goat milk. The International Official Analytical Chemistry Association (AOAC) and the Indonesian National Standard (SNI) methods were used to analyze the physical and chemical properties of yogurt. Yogurt was prepared using fermentation temperature (40, 43, 46°C), a combination of Streptococcus thermophilus and Lactobacillus acidophilus strains. (1: 1), culture inoculation (5, 10, 15persent) and fermentation times (8 hours). The results showed that the cultures concentration and temperature have a significant effect on physicochemical properties, and viable amount of fermented milk samples. There were a significant difference (P< 0.05) between all yogurt samples in LAB growth, total solids, pH, viscosity, and there were no significant difference (P< 0.05 between, titeriatble acidity, color and density of all samples. The general results of this present study proved that the ideal state of fermentation of cow and goat milks fermentation were: fermentation 46°C, culture concentration 10, 15%, for 8h. Thus, the benefit from these results are developing physical and chemical properties and sensory characteristics of cow and goat milk yogurt.