Comparative insights into the metabolite and taste discrepancies upon kimchi (Mukeunji) fermentation using different Lactobacillaceae starters.

Starter cultures play a key role in shaping the flavor and sensory traits of kimchi during fermentation. This study compared seven Lactobacillaceae starters using metabolite profiling and electronic tongue/nose analyses. A total of 46 key compounds were identified via UHPLC-Q-Orbitrap-MS and HPLC. Principal component analysis showed that metabolite and sensory changes were mainly influenced by specific starters and fermentation stages rather than species or genus. Amino acid derivatives, including glutamic acid, aspartic acid, γ-glutamic acid, serine, and γ-aminobutyric acid, showed differing concentrations depending on the starter and were associated with umami perception. Electronic tongue results indicated increased sourness and decreased sweetness and bitterness across all samples, while umami notably increased only with a specific starter. Aroma compounds detected by the electronic nose also followed starter- and time-based patterns. These findings provide practical guidance for selecting effective starter cultures to enhance the umami-rich flavor of aged kimchi (Mukeunji).