Using an autochthonous Lactiplantibacillus plantarum as a microbial starter to achieve precision flavor design in Allium chinense fermentation

1. Lactic acid bacteria were significantly related to characteristic flavor compounds. 2. L. plantarum was identified from aged pickle brine (PBa) fermented A. chinense bulbs. 3. L. plantarum inoculated fermentation promoted the formation of key volatile compounds. 4. Inoculated fermentation reduced undesirable sulfur-containing volatiles of A. chinense bulbs. The industrial production of fermented Allium chinense ( A. chinense ), a traditional food rich in bioactive compounds, faces major challenges in standardization and inconsistent flavor due to reliance on spontaneous fermentation. This study aimed to harness an autochthonous microbial resource to achieve precise flavor control. A dominant strain, Lactiplantibacillus plantarum L7, was isolated from aged pickle brine (PBa) and used as a starter culture (LP group). Its impact on flavor formation was systematically compared against natural fermentation (CG group) using a flavoromics approach integrating GC-IMS, GC-MS, E-tongue, and E-nose. Results showed that L. plantarum inoculation significantly enhanced the production of key volatile compounds, including esters (e.g., ethyl acetate, ethyl hexanoate) and terpenes, while effectively reducing undesirable sulfur-containing volatiles like dimethyl trisulfide. This metabolic shift resulted in a more refined flavor profile, characterized by significantly increased fruity and floral aromas and reduced pungency. Concurrently, the LP group exhibited higher concentrations of organic acids, particularly acetic acid, accelerating system acidification for improved microbial safety. Correlation analysis identified L. plantarum as a central metabolic driver, modulating pathways that link carbohydrate metabolism to the synthesis of critical flavor compounds. This study demonstrates that inoculated fermentation with the autochthonous L. plantarum L7 is a powerful strategy for precision flavor design. It thereby provides a scientific foundation and a readily applicable microbial starter for the standardized, industrial-scale production of A. chinense with superior and consistent sensory quality, paving the way for its development as a modern, reliable functional food.