| To isolate and identify lactic acid bacteria from Viili fermented milk and optimize the formulation of mixed starter cultures by determining appropriate strain ratios, this study aims to establish an effective approach. Methods Lactic acid bacteria were isolated using streak plating, and their taxonomic classification was determined through phylogenetic analysis based on 16SrRNA sequences. The composition of strain ratios in mixed cultures was designed with reference to the bacterial abundance observed in Viili fermented milk. Comprehensive analyses were performed to evaluate the acidity, exopolysaccharide production, textural properties, and volatile flavor compounds of the mixed fermentation groups. Results Diversity analysis identified four bacterial genera, among which Lactococcus, Streptococcus, and Leuconostoc were the dominant genera, comprising 49.12%, 40.67%, and 10.21% of the total bacterial composition, respectively. Lactococcus lactis H2, Streptococcus thermophilus H17, Leuconostoc mesenteroides H30, and Lactobacillus paracasei H33 were isolated and screened. A total of 20 fermentation trials with different strain compositions were designed to conduct a comprehensive assessment of key parameters, including pH, coagulation time, textural properties, exopolysaccharide content, and flavor profile. The results indicated that formulations S13 (H2:H17:H30:H33 = 11:4:4:1) and S17 (H2:H17:H30:H33 = 6:7:3:2) demonstrated the highest similarity to Viili fermented milk in terms of physicochemical and sensory properties. . Conclusion The blended formulations S13 (H2:H17:H30:H33 = 11:4:4:1) and S17 (H2:H17:H30:H33 = 6:7:3:2) exhibit promising potential as composite starter cultures. This study provides a theoretical basis for developing blended starter cultures in Viili fermented milk production. |
