Assessment of probiotic, biosafety and technological properties of lactic acid bacteria isolated from tarhana

This research investigated the probiotic potential of lactic acid bacteria isolated from tarhana, a traditional Turkish food. In this context, the probiotic, biosafety and technological properties of the strains previously identified as Enterococcus faecium, Lacticaseibacillus casei, Lactiplantibacillus plantarum, Leuconostoc citreum, L. mesenteroides, L. pseudomesenteroides, Limosilactibacillus fermentum, Pediococcus acidilactici, P. pentosaceus, Streptococcus thermophilus and Weissella cibaria were tested. All strains (except W. cibaria IST29) demonstrated tolerance to bile salts (83.78-115.30%), pepsin (65.27-126.52%), pancreatin (72.66-106.15%), and phenol (67.70-115.81%) at various levels. None of them (except L. plantarum IST7) showed hemolytic activity. The strains demonstrated different levels of sensitivity to the tested antibiotics. The proteolytic activity of the strains varied between 0.011 and 0.067 mg tyrosine/mL. The strains also showed antimicrobial activity (inhibition zone between 7 and 30 mm) against test microorganisms. The isolates showing the best gastrointestinal tolerance were tested for their ability to produce short-chain fatty acids and produced acetate, butyrate and propionate in the range of 11945-17715, 0.0580-0.1110 and 14335-22650 mu g/mL, respectively. The auto-aggregation and co-aggregation values of the strains ranged from 7.51 to 55.86% and 0.34-62.09%, respectively, while their xylene and ethyl acetate hydrophobicity were in the range of 69.40-91.81% and 72.36-95.21%, respectively. Their CaCo-2 cell adhesions ranged from 0.233 to 12.347%. Consequently, L. citreum IST9, L. fermentum IST13, L. fermentum IST14, and P. pentosaceus IST21 were identified as the most promising probiotic strains.