Effects of Pediococcus acidilactici and Rhizopus Oryzae on microbiota and metabolomic profiling in fermented dry-cure mutton sausages

Traditional fermentation of dry mutton sausages (DMSs) commonly causes some quality problems. In this study, high-throughput sequencing (HTS) and metabolomics were used to study the microorganisms and metabolites of DMSs produced by mixed strains of Pediococcus acidilactici and Rhizopus Oryzae, to discover the effect of inoculated fermentation (IF) on the metabolites of DMSs. A total of 92 volatile metabolites and 58 non-volatile significantly different metabolites were identified in DMSs. After inoculated fermentation, the volatile types increased, and the total contents of aldehydes and esters were enhanced at the end of fermentation. In addition, the levels of amino acids, fatty acids, palmitoyl carnitine, acetyl-l-carnitine, and betaine were also improved. The correlation analysis showed that the P. acidilactici and R. Oryzae were highly correlated with a variety of metabolites. Together, these findings provide excellent strain resources for improving the quality of mutton sausages.