Effects of compound fermentation of lactic acid bacteria IMAUJBP3 and IMAUJBR3 on the characteristic flavors and metabolites of mutton fermented sausages

Lactobacillus plantarum IMAUJBP3 and Limosilactobacillus reuteri IMAUJBR3 were used to prepare starter cultures. Through the electronic nose (E-nose), it was found that the compound fermentation can enhance the aromatic components in the product. Further analyses using Headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPMEGC–MS) and metabolomics revealed that the complex fermentation affected the oxidative breakdown of amino acids and lipids. HS-SPMEGC-MS identified 72 flavour compounds and found that the Mix group had the highest amount of ester compounds relative to the ZR group. In addition, of the 1402 metabolites identified by metabolomics, dihydroxyacetone phosphate was upregulated and most abundance in the Mix group. Dihydroxyacetone phosphate promotes the metabolism of carbohydrates and lipids, and affects the oxidative decomposition of amino acids and lipids, resulting in differences in flavor among meat products inoculated with different starter cultures. At the same time, it was also found that compound fermentation could down-regulate the compounds affecting product quality such as histamine, putrescine and phenethylamine. Overall, this study found that JBP3 and JBR3 in combination could improve the flavour quality of fermented lamb sausages. These findings may provide a good strain resource for improving the quality of lamb sausage.