Dynamic study on microbial communities and metabolites driven by functional lactic acid bacteria starter culture in rapid fermentation of mustard leaves ( Brassica juncea var. multiceps ) pickle

BACKGROUND: This study employed a composite inoculation fermentation process using Lactiplantibacillus plantarum and Saccharomyces cerevisiae to investigate the physical and chemical properties, metabolite changes, and dynamic changes in the microbial community succession of pickles during both the fermentation stage and the low-temperature storage stage. RESULTS: The nitrite and pH values of pickles decreased rapidly during the fermentation stage, whereas the total acidity increased and stabilised during the low-temperature storage stage. The organic acid content showed phasic changes; the highest Glu and Gln contents reached 28.39 mg per 100 g and 30.20 mg per 100 g, respectively, on day 5 of fermentation, giving the pickles a fresh flavor. The total content of volatile flavor components decreased during the fermentation stage, with a significant reduction in isothiocyanates, allowing other flavor components to emerge and form a harmonious complex flavor profile. High-throughput sequencing showed that L. plantarum rapidly became the dominant strain after inoculation, with a relative abundance of more than 60% on day 4 of fermentation, significantly inhibiting the growth of spoilage bacteria. CONCLUSION: The study showed that the inoculation of the composite bacterial agent can significantly shorten the fermentation time and achieve quality standardisation through directional regulation of microbial communities and metabolic pathways, which provides a theoretical basis and technical solutions for the industrial upgrading of traditional fermented foods. © 2026 Society of Chemical Industry.