Identification of dynamic changes in microbiota succession and metabolites of Chinese Fuling mustard tuber during fermentation by metagenomics combined metabolomics

This research aimed to investigate the correlation among microbial succession, metabolite and physicochemical properties over the fermentation periods of traditional Chinese fermented food Fuling mustard tuber via metabolomics and metagenomics. The results showed that the pH value and reducing sugar were significantly decreased (P < 0.05), while the titratable acidity and amino acid nitrogen were changed in an opposite manner. A total of 2811 metabolites were identified by non-targeted metabolomics analysis. Significant changes in metabolites were observed, including a marked decrease in glucosinolate levels and an increase in amino acids, dipeptides, and flavonoids (P < 0.05). Metagenomic analysis indicated a reduction in fungal and bacterial diversity, with Lactiplantibacillus plantarum , Latilactobacillus sakei , and unclassified_g__Lactiplantibacillus emerging as dominant bacterial species, and Debaryomyces hansenii as the predominant fungus. The microbiota influenced the flavor and nutritional quality of mustard tuber through pathways such as carbohydrate and amino acid metabolism. Aspergillus chevalieri , Leuconostoc carnosum , and Lactobacillus sp ZILC3-7 exhibited significant positive correlations with amino acids, dipeptides, flavonoids, and glucosinolates. Amino acid nitrogen and titratable acidity negatively correlated with most of the microorganisms. This study lays a theoretical groundwork for enhancing the fermentation process and improving Fuling mustard tuber quality through targeted use of functional microorganisms. • Metagenomics and metabolomics were employed to investigate mustard tuber metabolites and microbial compositions. • Five differential flavonoids were detected, including kolaflavanone, theaflavic acid, apigenin, luteolin, and nobiletin. • L. plantarum , L. sakei , and D. hansenii were the dominant microbial species in mustard tuber. • Carbohydrate metabolism and amino acid metabolism were principal pathways for flavor formation in Chinese Fuling mustard tuber. • Nobiletin were positively correlated with H. jeotgali , C. salexigens , and V. halodenitrificans in mustard tuber.