Differences of Free Amino Acids, Catechins and Caffeine Between Albino and Etiolated Tea Varieties

Abstract:

Green teas processed from shoots of albino tea varieties have an umami taste and premium qualities. In order to explore the taste quality and metabolite differences of green tea made from fresh leaves of albino and etiolated tea varieties, sensory evaluation and metabolite analysis were studied on 6 albino green tea varieties (milk white tea, NB) and 14 etiolated green tea varieties (golden tea, HJY) in Guangde City. Sensory evaluation showed that NB green teas taste fresh and convergence was slightly weak; the taste of HJY green tea had strong convergence and the freshness was lower than that of NB green tea. The total amount of free amino acids and the content of free amino acids with fresh and sweet taste in NB green teas were significantly higher than those in HJY green teas, while the contents of catechins and gallic acids contributing to convergence and the contents of bitter caffeine in NB green tea were significantly lower than those in HJY green teas. The partial least squares discriminant analysis showed that there were 7 signature compounds leading to the taste difference between the two green teas, which were theanine, arginine, glutamic acid, aspartate, epigallocatechin gallate (EGCG), epicatechin gallate and theobromine. The contribution of EGCG with the highest dose-over-threshold (Dot) to the flavor of HJY green tea was significantly higher than that of NB green tea. Therefore, the differences in contents of free amino acids, catechins, gallic acids and theophylline caused the different taste of albino and etiolated tea varieties.

Key words:Camellia sinensis;Albino tea;Etiolated tea;Green tea;Taste compound