Isolation and characterization of probiotic lactic acid bacteria from local yogurt and development of inulin-based synbiotic yogurt with the isolated bacteria

Abstract

Synbiotic yogurts can offer several potential benefits due to the combination of yogurts probiotics, prebiotics, and the nutritional qualities of milk. Local yogurt variants might add to the variety of probiotic alternatives because they frequently have distinct microbial communities. Employing indigenous strains not only represents cultural preferences but also increases the probability of obtaining bacteria adapted to the surrounding environment. This study was intended to isolate and characterize potential lactic acid bacterial strains from local yogurt and assess the effectiveness of inulin on the physicochemical and microbiological properties during the fermentation of synbiotic yogurt. A total of eight strains were identified and isolated. Two chosen isolates were combined with inulin at 0, 0.5, 1, and 1.5 % concentrations to produce synbiotic yogurts. The physicochemical and microbiological properties were assessed during the fermentation process of synbiotic yogurts. The result showed that the isolated Lactobacillus spp. and Streptococcus spp. strains had probiotic characteristics and good growth. After the fermentation, the yogurt sample containing 1.5 % inulin had the highest count of Lactobacillus spp. (8.17 ± 0.01 log CFU/ml) and Streptococcus spp. (8.03 ± 0.03 log CFU/ml), highest optical density (2.931 ± 0.001), acidity (1.43 ± 0.03), and water-holding capacity (63.54 ± 0.51), and lowest syneresis (34.75 ± 0.48). The addition of inulin did not affect color during the fermentation of synbiotic yogurt. This study concluded that inulin could boost yogurt's stability when combined with local lactic acid bacteria strains.