Correlation analysis between key volatile compounds and core functional bacterial community during Sichuan black tea processing

Microorganisms participate in the transformation of non-volatile compounds during black tea processing, while their effects on aroma remains unclear. In the present study, 132 KVCs (key volatile compounds) were identified in Sichuan black tea (SBT), of which, linalool and p-cymene were responsible for the citrus-like and sweet aroma of SBT. During the processing of SBT, Methylobacterium-Methylorubrum, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Pedobacter, Acidovorax, and Sphigomonas were the dominant bacterial genera. PCoA (principal components analysis)and Anoism (analysis of similarities) indicated that the bacterial community undergone subtle changes in various processes. Additionally, Pedobacter and Sphigomonas, core functional bacteria contributing to SBT aroma formation, act mainly by secreting enzymes related to amino acid conversion and glycoside hydrolysis. These enzymes include kynureninase, L-cysteate sulfo-lyase, homoserine dehydrogenase, serine/threonine protein phosphatase 1, and aminotransferase. Overall, these findings provide a deep insight into the potential mechanism of aroma formation under bacterial influence during SBT processing.