Investigation of Probiotic Attributes and Aromatic Components Produced by Lactic Acid Bacteria Isolated From Iranian Traditional Yogurts

Background: Yogurt is consumed in different ways all over the world owing to its high nutritional value, making it important to identify distinct strains from local producers with specific characteristics. Objectives: The purpose of the present study was to investigate the presence of probiotic bacterial populations in traditional yogurt, as an Iranian dairy product, and their effect on the probiotic specifications of yogurt. Methods: Initially, the isolation of lactic acid bacteria (LAB) was done using the culture method and then, the isolates were identified by examining their biochemical characteristics and 16S rRNA gene sequences. Finally, the characteristics of sensitivity to acidic conditions, bile salts, antimicrobial functions, survival rate, sensory properties, and aroma production for the isolates were evaluated. Results: Twelve isolates were identified from Lactobacillus and Enterococcus families. In general, the Lactobacillus plantarum strain KLDS 1.0725 exhibited the maximum ability to survive under acidic conditions. The L. plantarum strain KLDS 1.0725 and Enterococcus faecium strain FS019 had the highest survival in 0.3 and 0.5 % bile salts, respectively. L. plantarum WCFS1 and E. faecium Aus0004 created the maximum and minimum inhibition halos against all pathogens, respectively. The L. plantarum strain KLDS 1.0725 indicated enhanced abilities to produce acetaldehyde (25.59 ppm), while L. delbrueckii subsp. lactis illustrated the highest diacetyl production (5.96 ppm). The highest acceptability score in the sensory assessment was obtained for the L. plantarum strain KLDS 1.0725 and the E. faecalis strain V583. Conclusion: The overall results demonstrated the ability of isolated strains from yogurt to be applied in the industry, exhibiting desirable technological features and suitable aroma.