Mechanism of flavor formation in Suansun fermented by Lactiplantibacillus plantarum during a three-stage flavor formation model.

This study employed an integrated multi-omics approach-metagenomics, metatranscriptomics, and metabolomics-to elucidate the flavor formation mechanism in Suansun, leading to the proposal of a three-stage flavor formation model. In the initial stage, Lactiplantibacillus plantarum dominates pyruvate metabolism, rapidly producing lactic acid and creating an acidic environment that drives microbial succession. This pH shift initiates the key flavor-forming stage, during which peak levels of Weissella cibaria align with linalool biosynthesis, suggesting strong temporal coordination. During the mid-to-late stages, the abundance of Clostridium species was strongly correlated with p-cresol generation via tyrosine catabolism, while Lactococcus and related taxa produce nonanal and ketones through fatty acid β-oxidation. Overall, the starter culture actively restructures the fermentation niche, sequentially activating metabolic pathways in successive microbial communities to shape a stable flavor profile. This staged model of flavor evolution provides a scientific foundation for optimizing and controlling Suansun fermentation quality.