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

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.

Key words:air-dried beef;compound lactic acid bacteria;microbial diversity;high-throughput sequencing;non-targeted metabolomics