Insight into volatile metabolites and key odorants in black teas processed from Jianghua Kucha tea germplasm (Camellia sinensis var. assamica cv. Jianghua)

Jianghua Kucha (JHKC) is an ancient tea germplasm, which presents a high value for resource utilization but was less developed in aroma research. In this study, volatile metabolites in fresh leaves and corresponding black teas of JHKC, along with odorants of JHKC black teas were systematically investigated using stir-bar sorptive extraction in combination with gas chromatography–mass spectrometry (GC–MS) and GC–olfactometry/MS (GC–O/MS) technologies. A total of 128 and 135 volatile compounds were identified in fresh leaves and black teas, respectively, along with 13 key differential volatile components derived from fatty acids, pigments, glycoside precursors, and the terpene pathway. An odorant wheel for JHKC black teas was developed based on 29 important odorants determined through a combination of GC–O/MS perception, aroma extract dilution analysis, odor activity value measurement. Trans-β-Damascenone, cis-jasmone, and cis-jasmin lactone have been identified as significant contributors to the “sweet” flavor of JHKC black teas.