Unveiling key odor-active compounds and bacterial communities in Fu Brick tea from seven Chinese regions: A comprehensive sensomics analysis using GC-MS, GC-O, aroma recombination, omission, and high-throughput sequencing.

Fu Brick Tea (FBT) is a unique fermented tea produced in multiple regions of China, whose aroma qualities, key odor-active compounds and bacterial communities are not well characterized. By optimizing HS-SPME methods, utilizing GC-MS, GC-O, sensory analysis, aroma recombination and omission experiments, and bacterial sequencing, we revealed the primary volatiles and bacterial communities in 41 samples from 7 major producing regions. A total of 63 volatiles and 32 odor-active compounds were quantitatively analyzed using GC-MS and GC-O, respectively. Sensory analyses discriminated the quality of the samples. Differential analysis indicated that poor aroma FBTs had either low volatile content or excessive "green" notes. Key odor-active compounds in high-quality aroma FBTs include 1-octen-3-ol, phenylethylalcohol, β-ionone, dihydroactindiolide, and 1,2,3-trimethoxybenzene. Sequencing results identified Bacillus, Pseudomonas, and Streptococcus as dominant genera. Functional prediction analyses suggest that bacteria contribute to the formation of FBT aroma. This study offers new insights into the quality characteristics of FBT.