Camellia kucha (Chang et Wang) Chang is a special tea in China, which is extremely bitter but beneficial for human health. However, there are no systematic studies on Kucha metabolites, especially those associated with bitterness. In this study, a non-targeted metabolomics approach based on UHPLC-LTQ-Orbitrap-MS was applied to comprehensively profile the characteristic metabolites of two Kucha cultivars by comparison with three common tea cultivars. A total of 90 differential metabolites were identified. Among them, eight key metabolites (theacrine, 2,4-dimethyl-1H-indole, EGCG, dihydrokaempferol, panasenoside, 3-cresotinic acid, 3-methylglutaconic acid, and L -histidine) were more abundant in Kucha than in the controls, most of which were positively correlated with bitterness. Furthermore, quantitative analysis of some important catechins and alkaloids by HPLC implied absolutely higher concentrations of EGCG and theacrine in Kucha, which was similar to the metabolomics results. These results will be contribute to future research on the bitter and nutritional properties of Kucha.
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.
危险品化学品经营许可证（带存储）