Multi-omics analysis of microbial communities and metabolites during the fermentation of traditional Midu Juanti

The current study employed a combination of high-throughput sequencing and non-targeted metabolomics techniques to elucidate the changes in the quality, microbial communities, and metabolites throughout the fermentation process of traditional Midu Juanti, a traditional fermented meat product that originates from ethnic minority regions in southwestern China. The findings show that 22 dominant genera (7 bacterial and 15 fungal genera), with a relative abundance >1%, were successfully identified during the fermentation of Midu Juanti. Additionally, 979 metabolites were identified using the Human Metabolome Database (HMDB) annotation. Among these, lipids and lipid-like molecules constituted the largest proportion, followed by organic acids and their derivatives. Moreover, based on the variable importance in the projection (VIP) > 2 and P < 0.05, 60 differentially changed metabolites (DCMs) were identified. Meanwhile, the presence of Lactobacillus was positively correlated with 54 DCMs (P < 0.05, |r| > 0.5), including tryptophyl-threonine and (5R)-5-hydroxyhexanoic acid. Conversely, a negative correlation was observed between the presence of Monascus and these 54 DCMs (P < 0.05, |r| > 0.5). This study has the potential to enhance the processing theory of fermented meat products and establish a solid theoretical foundation for the control and enhancement of the quality of Midu Juanti.