Abstract

Twenty three indigenous isolates of yeast (Saccharomyces cerevisiae) obtained from various traditional fermented foods and traditional inocula of Western Himalayas (Himachal Pradesh) were subjected to in vitro probiotic tests. All the isolates were found to be intrinsically tolerant to upper gastrointestinal transit and this property was isolate dependent. Reduction in viability (in terms of log CFU/ml cells) was more in simulated gastric juice of pH 2 as compared to pH 3. These isolates were also investigated for surface hydrophobicity and autoaggregation abilities. Nine yeast isolates produced exopolysaccharide and four exhibited antioxidative activity using 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay (in methanol and buffered methanol reaction systems). Interestingly, one indigenous yeast isolate (Sc15) was found positive for siderophore production, whereas none of the isolates was positive for bile salt deconjugation activity (towards glycine and taurine conjugated bile salts) and galactosidase enzyme production.

Key words: Probiotics, yeast isolates, simulated gastric and intestinal juices, Western Himalayas, antioxidant, exopolysaccharide.