Probiotic nature of goat milk yogurt fermented by Bifidobacterium sp. from human source

Bifidobacteria were isolated from three infants (2 - 7 days old). Bifidobacteria is a predominant probiotic organism in infant feces due to bifidogenic factors present in human milk. The isolates were characterized by microbiological, biochemical and fructose-6-phospho-ketolase tests and screened for probiotic properties such as acid-bile tolerance and antibiotic sensitivity. The best isolate, Bif 3 was used to prepare set-type yogurt using goat milk. Goat milk was supplemented with whey protein concentrate (WPC), soy protein isolate (SPI) and skimmed milk powder was added to increase the total solid content for optimal curd tension and to improve gel firmness Goat milk yogurt was prepared with 1.25% WPC and SPI each and tested for the viability of starter and probiotic cultures against plain goat milk yogurt (control) during the storage period of 7 days at 4°C. During the fermentation, the supplemented goat milk showed faster acidification rate. The incubation time was reduced for proteins supplemented sample which attained desirable pH of 4.6 within 6 h while control required 8 h. The supplemented goat milk yogurt showed optimum survival of Bifidobacterium isolate during week storage. The overall sensory and quality acceptance of supplemented goat milk sample was also better than plain goat milk yogurt.