Abstract:The biochemical composition and antioxidative activity of three varieties of aged tea, including black tea, oolong tea and dark tea, were determined in this study. The contents of water extracts, tea polyphenols, total flavonoids, total soluble sugars, free amino acids, total soluble sugar theaflavins, thearubigins and theabrownin in these tea samples were determined by colorimetry. High performance liquid chromatography was used to analyze the contents of gallic acid, caffeine and catechin monomer in these aged tea samples. The total antioxidant capacity was determined by FRAP method. The results showed that there was a significant difference in the contents of the main quality biochemical components in the different aged tea samples. There was also a significant difference in the contents of the main biochemical components in the aged tea samples of different tea varieties or regions. No EGC was detected in tea samples from three different teas. Neither GC or CG was detected in aged black tea samples. GC and EGCG contents in aged oolong tea samples were significantly higher than those in other tea samples. The content of GA in black tea samples was generally low, and the components of catechins in Yunnan pu brick tea were not detected. The total antioxidant capacity of different tea aged tea samples differed greatly. Among them, the aged Qianjiazhai Shengpu tea had the strongest antioxidant capacity, and its antioxidant capacity of tea is related to the total contents of tea polyphenols and catechins.
