Untargeted metabolomics reveals flavor and metabolic changes in mixed Lactobacillus-fermented black mulberry juice

This study aimed to investigate metabolic differences between mixed- and single-culture fermentation in black mulberry juice (BMJ). Using E-nose, E-tongue, and metabolomics, we analyzed metabolic profile variations and flavor compounds in BMJ fermented with different lactic acid bacteria (LAB). Results demonstrated that BMJ is an excellent fermentation substrate, with both cultures achieving colony counts exceeding 8 log CFU/mL after fermentation. Volcano plot and cluster analyses revealed that single-culture fermentation exhibited higher efficiency in biotransforming and degrading specific compounds, yet its metabolic profile was less diverse. In contrast, mixed-culture fermentation enhanced metabolic diversity through complementary pathways among strains, improving complex molecule production, optimizing flavors, reducing bitterness/astringency, and minimizing vitamin loss. This research provides a foundation for fermented mulberry beverage development. Future studies could integrate multi-omics analyses to advance industrial applications.