Evaluation of different quality parameters of goat milk yoghurt developed using selected lactic acid bacteria

The present study was undertaken to develop yoghurt from goat milk and to assess its sensory, chemical, microbiological and storage quality. Three different cultures were tried and incubation temperatures viz. 30, 37 and 42°C were selected. Yoghurt was prepared using 3% mixed culture containing Streptococcus thermophillus and Lactobacillus bulgaricus NCDC 144 in the ratio of 1: 1. The product was prepared in five replicates and analysed for sensory attributes such as flavor, body and texture, colour and appearance and overall acceptability on 9-point hedonic scale by a panel of five judges. Based on overall acceptability of the product, the best incubation temperature (42°C) was selected. The product prepared with optimized incubation temperature was further subjected for chemical, microbiological and storage quality. It was observed that goat milk yoghurt contains less percentage of total solids and higher titrable acidity than cow milk yoghurt. The sensory and microbiological quality of the product was evaluated on 0, 3, 6 and 9 days at refrigeration temperature (4±1°C) to assess the storage stability of the product. The sensory attributes change significantly (p#0.05) after 9^th day of storage in control and developed product both. The product had total plate count of 10⁶ cfu and decreased significantly (p#0.05) after 9^th day of storage (10⁴ cfu/g). The coliform and yeast and mould count were not detected, both in control and developed product throughout storage period. It may be concluded that good quality goat milk yoghurt can be prepared by using mixed culture at 3% concentration with incubation temperature of 42°C for 8 hours.