Cancer Prevention Laboratory , Colorado State University , Fort Collins , Colorado 80523 , United States.
Department of Food Science , Rutgers, The State University of New Jersey , New Brunswick , New Jersey 08901 , United States.
J Agric Food Chem. 2019 May 15;67(19):5423-5436. doi: 10.1021/acs.jafc.8b05140. Epub 2018 Nov 26.
While the Camellia sinensis cultivar and processing method are key factors that affect tea flavor and aroma, the chemical changes in nonvolatile components associated with the tea processing method using a single cultivar of C. sinensis have not been reported. Fresh leaves from C. sinensis Longjing 43 were subjected to six tea processing methods and evaluated by targeted and untargeted chromatographic procedures. On the basis of targeted assessment of the total catechin content, three clusters were identified: yellow-green, oolong-white-dark, and black. However, principal component analysis of the total tea metabolome identified four chemical phenotypes: green-yellow, oolong, black-white, and dark. Differences in the non-catechin components included amino acids and γ-aminobutyric acid, which increased in white tea, and dihydroxyphenylalanine, valine, betaine, and theophylline, which increased in dark tea. Overall, this study identified a wide range of chemicals that are affected by commonly used tea processing methods and potentially affect the bioactivity of various tea types.
虽然茶树品种和加工方法是影响茶叶风味和香气的关键因素，但使用单一品种的茶树进行加工时，与非挥发性成分相关的化学变化尚未有报道。本研究采用龙井 43 鲜叶，通过有针对性和非靶向性的色谱程序，对其进行了 6 种茶加工方法的处理和评估。基于对总儿茶素含量的靶向评估，将其分为 3 个聚类：黄-绿、乌龙-白-暗和黑。然而，总茶代谢物的主成分分析确定了 4 种化学表型：绿-黄、乌龙、黑-白和暗。非儿茶素成分的差异包括白茶中氨基酸和γ-氨基丁酸的增加，以及黑茶中二羟苯丙氨酸、缬氨酸、甜菜碱和茶碱的增加。总的来说，本研究鉴定了广泛受常用茶叶加工方法影响的化学物质，这些物质可能影响各种茶叶类型的生物活性。
