No abstract

Probiotics are living microorganisms which impart beneficial effects to consumers when ingested in a certain quantity. The main probiotic groups include the strains of genera Lactobacillus, Bifidobacterium, Lactococcus and Streptococcus. Probiotics are similar to the naturally found intestinal gut microflora which play an important role in enhancing the human and animal health. Probiotic microorganisms provide various health benefits to human, reduce the blood pressure, decrease the serum cholesterol level, lactose digestion and improve immune response etc. They provide health benefits to the consumers by various mechanisms such as by producing the different postbiotics (bacteriocins, lactic acid), build up the epithelial barrier, fight for binding sites with pathogens on gut wall and thus preventing the infection and enhancing the adhesion to intestinal mucosa. Thus, probiotics having therapeutic values are used for the treatment of various diseases and illness such as allergy, cancer, gastrointestinal disorders, urogenital infections, to reduce obesity, cholesterolaemia and diarrhea. Due to their numerous health benefits, probiotics are gaining more attention among researchers and consumers. More research is needed on probiotics and their action mechanisms which will provide suitable probiotic strain for treatment/prevention of diseases. This review presents the role of probiotic microorganisms in sustaining and improving the health of human being.

Fermented foods and beverages are rich source of probiotic microorganisms and yeasts are the most common microorganisms found in these fermented products. Fermented beverages are less explored for probiotics, therefore; the present study was focused on isolation, screening and characterization of probiotic yeast from rice Chhang, a fermented beverage of Lahaul Spiti. Ten yeast isolates were initially isolated from rice Chhang and out of which two isolates Saccharomyces cerevisiae Y196 and Saccharomyces cerevisiae Y197 were selected based on their antimicrobial activity. These two yeast isolates were examined for various probiotic properties such as survival at low pH, bile tolerance, microbial adhesion to hydrocarbons, cholesterol assimilation, exopolysaccharide production and haemolytic activity. Both isolates showed antimicrobial activity against all the tested pathogens used in this study, also showed high acid tolerance at pH 2 and pH 3 and can withstand high bile concentration as compared to control. Percentage of hydrophobicity was found to be 57 % and 41 % in Saccharomyces cerevisiae Y196 and Saccharomyces cerevisiae Y197, respectively. Both isolates were able to show high cholesterol assimilation with a maximum of 90 % in case of Saccharomyces cerevisiae Y197 with taurocholate. They were also found to be positive for exopolysaccharide production and showed no haemolytic activity. Hence, keeping in view the results of present study, these isolates can be proposed for preparation of various probiotic food products.

Background Fermented foods are the results of metabolic activities of various microorganisms. People have traditionally known how to culture desirable microorganisms, primarily lactic acid bacteria, yeasts, and filamentous molds, for the manufacture of edible foods. Yeast isolated from home-made mango pickle from Hamirpur, Himachal Pradesh, was assessed for probiotic properties and their enzymatic profiling. Results Four yeast isolates were isolated out of which P. kudriavzevii Y33 was selected on the basis of high acid tolerance as well as broadest antimicrobial activity. The selected isolate was observed to have high acid tolerance at pH 2 and show strong antimicrobial activity against all the pathogens examined. P. kudriavzevii Y33 can also withstand high bile concentration and showed high viability index, i.e., 95% at concentration of 2% of bile. The isolate was able to demonstrate high cholesterol assimilation in medium containing ox bile and taurocholate, at 88.58 and 86.83%, respectively. The autoaggregation ability of isolate increases with increasing the time of incubation and showed 87% of autoaggregation after 24 h of incubation. P. kudriavzevii Y33 exhibited resistance towards different antibiotics, found to be positive for exopolysaccharide production and showed no hemolytic activity. The isolate was observed to produce several enzymes such as β-galactosidase, protease, amylase, phytase, and lipase. Conclusions The results of the current study revealed that P. kudriavzevii Y33 has various beneficial qualities that suggest it could be used as probiotics. Enzymes produced by yeast isolate help in improving flavor and mineral availability in the fermented products.