Untargeted metabolomics reveals flavor and metabolic changes in mixed Lactobacillus-fermented black mulberry juice
Mingshan Lv, Xiaolu Liu, Ruoqing Liu, Aihemaitijiang Aihaiti, Jingyang Hong, Zheng Li, Jun Xing, Yincang Cui, Liang Wang
Abstract
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. • Mixed-strain fermentation showed the strongest acid production capability. • Different LAB exhibited distinct flavor characteristics in black mulberry juice. • LAB fermentation reduced phenolic content in BMJ at later stages. • Pyruvate and l -aspartate were central metabolites for all six LAB strains. • LAB fermentation mainly involved the TCA cycle and phenylalanine metabolism.