Lactobacillus fermentum strains with significant probiotic and antioxidant potential

Abstract

The growing demand for dairy products amended with probiotics has led to the exploration of new beneficial microorganisms such as probiotics with beneficial properties. In the present work, the probiotic and antioxidant potential of Lactobacillus fermentum strains isolated from dairy products were evaluated. Strains were investigated for their probiotic properties by performing different tests such as survival in pepsin, low pH, and bile salt, antibacterial activity, and antioxidant potential. These strains were further evaluated for their utilisation in yogurt formation as a probiotic. The isolated strains were identified as L. fermentum Y1, L. fermentum Y2, and L. fermentum C by 16S rRNA sequencing. All strains showed greater survival ability in simulated gastric conditions (pH 2.2 + pepsin) and in the presence of 0.3% bile salt. The highest antibacterial activity was exhibited by L. fermentum Y1 against Bacillus cereus. Among these three strains, L. fermentum Y1 had the highest reducing power, and L. fermentum C had the highest DPPH scavenging activity. All Lactobacillus strains as a single inoculum or in consortium showed significant (p < 0.05) probiotic properties by maintaining pH, titratable acidity, solid content, and high water holding capacity in comparison to the control in the cow yogurt and homogenised milk. The isolated Lactobacillus strains may be a potential source of probiotics in commercial yogurt preparation.