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 ۱۶S 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 ۱.۰۷۲۵ exhibited the maximum ability to survive under acidic conditions. The L. plantarum strain KLDS ۱.۰۷۲۵ and Enterococcus faecium strain FS۰۱۹ had the highest survival in ۰.۳ and ۰.۵ % bile salts, respectively. L. plantarum WCFS۱ and E. faecium Aus۰۰۰۴ created the maximum and minimum inhibition halos against all pathogens, respectively. The L. plantarum strain KLDS ۱.۰۷۲۵ indicated enhanced abilities to produce acetaldehyde (۲۵.۵۹ ppm), while L. delbrueckii subsp. lactis illustrated the highest diacetyl production (۵.۹۶ ppm). The highest acceptability score in the sensory assessment was obtained for the L. plantarum strain KLDS ۱.۰۷۲۵ and the E. faecalis strain V۵۸۳.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.

کلیدواژه ها:

Acetaldehyde ، Enterococcus ، lactobacillus ، Probiotic ، Yogurt