Probiotic and Functional Profiling of Yeast Isolates from Traditionally Fermented Yak Milk Products of Sikkim Himalayas

Growing health-enhancing awareness has promoted the inclusion of fermented foods in daily diets. In this study, 850 yeasts were isolated from yak dahi and chhurpi, out of which only 15 were further screened. These isolates were identified as Yarrowia lipolytica (5), Saccharomyces cerevisiae (4), Kluyveromyces lactis (2), Kluyveromyces marxianus (1), Wickerhamomyces anomalus (1), Candida parapsilosis (1), and Candida metapsilosis (1). These isolates exhibited probiotic traits and showed no safety concern based on in-vitro safety evaluation. Further, these isolates have demonstrated cholesterol-lowering activity, antioxidant activity, anti-inflammatory activity, and antidiabetic activity relevant functional attributes. PCA biplot analysis obtained from the variance-covariance matrix at a 10k bootstrap value indicated Saccharomyces cerevisiae DUAY-53 from yak dahi and Kluyveromyces lactis CUBY-19 from yak chhurpi have the highest potential as probiotic yeast. The findings highlight fermented yak milk as a valuable reservoir of safe and robust probiotic yeasts, suitable for use in functional food development.