Abstract: The aim of this study was to investigate the effects of different aroma-firing​ temperatures on the aroma quality of Sichuan Congou black tea. Three aroma-firing temperatures (60, 80, and 100 ℃) were evaluated. Sensory evaluation, gas chromatography-mass spectrometry (GC-MS), multivariate statistical analysis, and relative odor activity value (ROAV) analysis were employed to study the sensory quality, major biochemical components, and volatile metabolites of Sichuan Congou black tea. Sensory evaluation results showed that Sichuan Congou black tea baked at 100 ℃ achieved the highest overall sensory score and aroma score, exhibiting a citrusy candy-like aroma with a sweet note. Its tea polyphenol content decreased significantly, while its thearubigins (TRs), epigallocatechin (EGC), and catechin (C) contents increased significantly (P < 0.05) compared with the other treatments. A total of 246 volatile components and 75 differential metabolites were identified across all samples, the main ones being hydrocarbons, ketones, and alcohols. Cluster analysis revealed that control samples and samples baked at 60 ℃ were clustered into one group, while samples baked at 80 and 100 ℃ were clustered into another group. Based on ROAV analysis and flavor annotation, 19 compounds, including (E,Z)-2,6-nonadienal and 6-methyl-2-heptanone, were identified as the key differential aroma components for distinguishing Sichuan Congou black tea treated at different aroma-firing temperatures. Furthermore, decanal, p-cymene, (E)-3,7-dimethyl-2,6-octadienal, and 6-methyl-5-hepten-2-one played crucial roles in the formation of the citrusy candy-like aroma of Sichuan Congou black tea. This study provides a theoretical basis for the high-quality and efficient processing of Sichuan Congou black tea.

Key words: Sichuan Congou black tea; aroma-firing temperature; flavor quality; gas chromatography-mass spectrometry; relative odor activity value