传统与强化发酵羊肉香肠微生物多样性及代谢物差异分析

为探究发酵方式对羊肉香肠中微生物群落和代谢物影响，采用高通量测序和代谢组学技术分析传统（CT）和强化（QH）发酵羊肉香肠中的微生物群落及代谢物差异，及微生物与差异显著代谢物之间的相关性。结果表明，强化发酵对羊肉香肠微生物群落有明显的影响。属水平上，CT以明串珠菌属（Leuconostoc）、拉恩氏菌属（Rahnella）、环丝菌属（Brochothrix）、德巴利氏酵母属（Debaryomyces）占优势；QH以明串珠菌属、环丝菌属、嗜冷杆菌属（Psychrobacter）、片球菌属（Pediococcus）、德巴利氏酵母属、青霉属（Penicillium）占优势。代谢物方面，强化发酵增加了风味和滋味物质的种类和含量，尤其是酯类和氨基酸类。基于多元统计分析，共鉴定出29 个挥发性和16 个非挥发性显著差异代谢物（|差异倍数|＞2且变量重要性投影＞1，P＜0.05）；相关性结果表明，7 个细菌属（明串珠菌属、环丝菌属、片球菌属、嗜冷杆菌属、肠球菌属（Enterococcus）、拉恩氏菌属和葡萄球菌属（Staphylococcus））和7 个真菌属（德巴利氏酵母属、青霉属、曲霉属（Aspergillus）、unspecified_Aspergillaceae、unspecified_Capnodiales、根霉属（Rhizopus）和unspecified_Basidiomycota）被视为核心微生物（|r|＞0.8，P＜0.05）。

Differences in Microbial Diversity and Metabolites in Naturally Fermented and Starter Culture-Fermented Mutton Sausages

To explore the effects of fermentation methods on the microbial communities and metabolites in dry fermented mutton sausages, the differences in the microbial communities and metabolites in naturally fermented and starter culture-fermented mutton sausages were analyzed by high-throughput sequencing and metabolomics, and the correlation between microbial communities and significantly differential metabolites (SDM) was investigated. The results showed that inoculated fermentation had obvious effect on the microbial community of mutton sausages. At the genus level, Leuconostoc, Rahnella, Brochothrix and Debaryomyces were dominant during natural fermentation, and Leuconostoc, Brochothrix, Psychrobacter, Pediococcus, Debaryomyces and Penicillium were dominant during inoculated fermentation. Inoculate fermentation increased the types and contents of flavor substances, especially esters and amino acids. Based on multivariate statistical analysis, 29 volatile metabolites and 16 non-volatile metabolites that significantly differed between the natural and inoculated fermentation groups were identified (fold change (FC) > 2, variable importance in the projection (VIP) > 1, P < 0.05). Besides, correlation analysis showed that seven bacterial genera (Leuconostoc, Brochothrix, Pediococcus, Psychrobacter, Enterococcus, Rahnella and Staphylococcus) and seven fungal genera (Debaryomyces, Penicillium, Aspergillus, unspecified_Aspergillaceae, unspecified_Capnodiales, unspecified_Capnodiales, Rhizopus and unspecified_Basidiomycota) were regarded as core microorganisms (| r | > 0.8, P < 0.05).