Insight into the Chemical Compositions of Anhua Dark Teas Derived from Identical Tea Materials: A Multi-Omics, Electronic Sensory, and Microbial Sequencing Analysis

Anhua dark teas (DTs) are unique fermented teas from China's Anhua County. Metabolomics and volatolomics, utilizing untargeted (UHPLC-Q-Exactive Orbitrap-MS and GC×GC-TOF-MS) and targeted (UHPLC-QqQ-MS and GC-QqQ-MS) approaches, along with electronic sensory assessments (E-tongue/nose/eye), were used to analyze and compare chemical compositions and sensory characteristics of five Anhua DTs. All of these teas were derived from identical tea materials. The chemical compositions differed significantly among five Anhua DTs, with Tianjian tea being particularly notable. Among five Anhua DTs, long-lasting fermentation and complex processing methods led to transformation of multiple compounds, particularly catechins. Eighteen volatile compounds with OVA>1 were key aroma contributors in Anhua DTs, with some compounds related to degradation of fatty acids. Aspergillus, Pseudomonas, and Bacillus are dominant microorganisms in Anhua DTs. Furthermore, this study unveiled notable differences in chemical compositions between Anhua DTs and five other kinds of tea. This research enhances our understanding of Anhua DTs processing.