Impact of selenium-enriched L igilactobacillus salivarius DACN818 on Zhacai: Insights from metabolomics and microbiomics.

Selenium enrichment can modulate the metabolic activities of microorganisms, yet how such changes influence the quality characteristics of fermented foods remains poorly understood. This study investigated the effects of L igilactobacillus salivarius DACN818 and its selenium-enriched variant (Se-DACN818) on the quality of Zhacai (Made from Brassica juncea var. tumida Tsen et Lee). Compared to the Control group at day 7, inoculation with Se-DACN818 increased the total content of volatile flavor compounds by 32.7%, with notable increases in alcohols, ketones, and esters. Additionally, compared to the DACN818 group, Se-DACN818 reduced pungent isothiocyanates by 55.37%; compared to the Control group, it decreased nitrite content by 53% and reduced brittleness by 17.6%. Metabolomics analysis revealed that Se-DACN818 enhanced the abundance of umami- and aroma-related compounds, including N2-maltulosylarginine and Ile-Asp-Glu. Correlation analysis showed significant positive associations between these umami- and aroma-related compounds and the abundance of Ligilactobacillus, whereas brittleness and protopectin content were significantly negatively correlated with the abundance of Pediococcus. This work provides a new strategy for enhancing the quality of fermented vegetables through selenium-enriched fermentation.