Multidimensional evaluation of techno-functional properties of yoghurt bacteria

Microbial diversity in traditional foods is decreasing due to widespread industrial production, using a limited number of strains, and industrial products as starter cultures in homemade production. Yoghurt is a fermented product, and this decrease is most common. This study investigated the microbiological and physicochemical properties of 82 traditional and 37 industrial yoghurt samples. Four hundred thirtynine lactic acid bacteria isolated were molecularly identified. Of the isolates, 223 were Lactobacillus bulgaricus, and 216 were Streptococcus thermophilus. Characteristics of the isolates such as acidification, arginine hydrolysis and gas production from glucose, H2O2 production, growth at different temperatures, pH and NaCl concentrations, exopolysaccharide production, proteolytic and lipolytic activity, L (+) lactic acid production, cholesterol assimilation, haemolytic activity, DNase activity, antibiotic resistance, and virulence gene were investigated. As a result, 4 L. bulgaricus and 6 S. thermophilus isolates were the best starter cultures for yoghurt production.(c) 2023 Elsevier Ltd. All rights reserved.