不同茶类陈年茶的生化成分分析及其抗氧化活性

本文研究了三个不同茶类陈年茶的生化成分及其抗氧化活性。采用比色法测定了这些茶样中水浸出物、茶多酚、总黄酮、可溶性总糖、游离氨基酸、茶黄素、茶红素及茶褐素的含量,同时采用高效液相色谱仪测定了这些陈年茶样中没食子酸、儿茶素单体及咖啡碱含量,采用FRAP法测定了其总抗氧化能力。结果显示不同茶类陈年茶样中主要品质生化成分含量相差较大,同一茶类不同品种或产地的陈年老茶样中主要品质生化成分含量也有差别。三个不同茶类供试茶样中EGC均未检出;陈年红茶样中GC和CG未检出;陈年乌龙茶样中GC和EGCG含量显著高于其他茶叶;陈年黑茶样中GA含量普遍较低,滇药香熟普砖茶中各儿茶素组分均未检出。不同茶类陈年茶样总抗氧化能力相差较大,其中以陈年千家寨生普散茶的抗氧化能力最强,且它的抗氧化活性与其茶多酚和儿茶素总含量呈浓度依赖关系。

Biochemical Component Analysis and Antioxidant Activities of Different Kinds of Aged Tea

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.