Comparative study of volatile compounds and metabolic pathways of Congou black tea from four regions based on sensory evaluation and HS-SPME/GC–MS

Abstract

Black tea cultivation spans various regions in China, where the economic value of black tea significantly varies based on geographical origin. This study examined Congou black teas originating from Sichuan (SC), Zhejiang (ZJ), Jiangxi (JX), and Fujian (FJ) using headspace solid phase microextraction and gas chromatography-mass spectrometry (HS-SPME/GC–MS), identifying 16 key volatile compounds (rOAV > 1). Notably, eight volatile compounds were consistently found in all Congou black teas. Employing partial least squares discriminant analysis (PLS-DA) effectively discriminated between the four kinds of Congou black teas, identifying 12, 14, 11, and 11 volatile compounds as distinct markers for Sichuan, Zhejiang, Jiangxi, and Fujian variants, respectively. Sensory analysis revealed that SC Congou black tea had a citrus, sweet and slightly almond flavor, FJ Congou black tea had floral and minty aromas, JX Congou black tea had fruity and sweet aromas, and ZJ Congou black tea had a sweet aroma and a lingering aroma of aged leaves. These distinct metabolites were found to enrich into 8 specific metabolic pathways. The study showed that there were some differences in the volatile compounds in Congou black tea from different regions, which further provided some theoretical basis for distinguishing the differences in volatile compounds and sensory properties of Congou black tea from different geographical origins in China.