复合乳酸菌发酵对风干牛肉细菌多样性及代谢物的影响

Effects of compound lactic acid bacteria on the bacterial diversity and metabolites in the fermentation of air-dried beef

摘要:

【目的】 探究接种复合乳酸菌对风干牛肉发酵过程中微生物多样性及代谢物的影响。【方法】 以团队前期分离得到的不同乳酸菌为发酵剂，采用5种复配方式将乳酸菌接种到牛肉中进行发酵。具体分组与复配比例如下：C组为格氏乳球菌(Lactococcus garvieae) TC-6:戊糖片球菌(Pediococcus pentosaceus) TMR-WJG，按1:1比例混合；D组为格氏乳球菌:乳酸乳球菌(Lactococcus lactis) TC-2按1:1比例混合；G组为戊糖片球菌:乳酸乳球菌按1:1比例混合；H组为乳酸乳球菌:戊糖片球菌:格氏乳球菌按1:1:1比例混合；K组自然发酵，不接种乳酸菌。采用高通量测序技术和非靶向代谢组学技术对接种了不同复合乳酸菌的风干牛肉的细菌群落结构及其代谢产物进行研究。【结果】 在所有接种了乳酸菌的风干牛肉中，共检测到19门223属304种细菌，其中以嗜冷杆菌为主要菌群，平均相对丰度为52.21%。非靶向代谢组学结果表明，共发现了1 782个具有显著差异的代谢物，这些代谢物包括生物碱、脂类、有机酸和其他与风味形成相关的化合物。微生物组和代谢组相关性分析表明，接种不同发酵剂导致风干牛肉中细菌群落结构差异显著，从而对其代谢产物产生影响，特别是接种了戊糖片球菌和格氏乳球菌的风干牛肉(C组)与自然发酵组(K组)之间差异显著(p<0.05)，其中香豆素和鞣料云实素显著下调，山茶苷A、十八碳二烯酸酯和脂质体Ⅱ显著上调。【结论】 本研究选用的复配乳酸菌对风干牛肉中菌群结构影响显著，风干牛肉品质形成可能与微生物菌群结构及微生物代谢物相关，选取的复配乳酸菌具有潜在的应用价值。

Abstract:

[Objective] To explore the effects of compound lactic acid bacteria on the bacterial diversity and metabolites in the fermentation process of air-dried beef. [Methods] The lactic acid bacteria isolated in the early stage were inoculated into beef for fermentation with different strain combinations: C (Lactococcus garvieae TC-6:Pediococcus pentosaceus TMR-WJG, 1:1), D (L. garvieae TC-6:L. lactis TC-2, 1:1), G (P. pentosaceus TMR-WJG:L. lactis TC-2, 1:1), H (L. garvieae TC-6:P. pentosaceus TMR-WJG: L. lactis TC-2, 1:1:1), and K (without inoculation). High-throughput sequencing and non-targeted metabolomics were employed to study the bacterial community structure and metabolites, respectively, in air-dried beef inoculated with different combinations of lactic acid bacteria. [Results] A total of 304 species of bacteria belonging to 223 genera of 19 phyla were detected. Psychrobacter was predominant in the air-dried beef, with the average relative abundance of 52.21%. A total of 1 782 significantly differential metabolites were identified, including alkaloids, lipids, organic acids, and other metabolites related to flavor formation. The correlation analysis between microbiome and metabolome confirmed that the structures of bacterial communities differed significantly in the air-dried beef samples with different starters, which contributed to the differences of metabolites between groups, especially between groups C and K (P<0.05). Specifically, the inoculation lowered the levels of coumarin and corilagin and elevated the levels of camellianin A, octadecadienoate, and lippioside II. [Conclusion] The compound lactic acid bacteria selected in this study had a significant effect on the microbial community structure in air-dried beef. The quality formation of air-dried beef may be related to the microbial community structure and microbial metabolites. The compound lactic acid bacteria selected in this study demonstrated a potential application value.