Study of the quality and functional properties of Chinese green tea samples

The article is devoted to the study of the quality of the Chinese green tea samples of different manufacturers. Special attention is paid to the functional properties of green tea due to polyphenol compounds and water-soluble vitamins P and C. The Chinese green tea of such manufacturers as “Tian Ren”, grown on upland plantations in China, “Riston” jasmine tea, “Ahmad” tea produced in accordance with ancient recipe of health and beauty of Jang Mi, “Greenfield Flying Dragon” tea are selected for analysis. Integrated research of green tea samples gives the possibility to define general concentration of water-soluble extracts from43,82 % of “Tian Ren” tea and 38,35 % of “Greenfield Flying Dragon” tea. To have a full characteristic of water-soluble dry substances it is stated general concentration of polyphenol, tannin and caffeine. General concentration of polyphenol is defined by the colorimetric method with the use of Folin-Ciocalteu reactive. The best parameters are shown with the sample of “Tian Ren” grown on the upland plantations of China.It is well known that vitamins P and C possess antioxidant properties. The results of research show that all samples of tea contain these vitamins in significant quantities, which can be explained by the lack of operation of fermentation in the production of green tea. Determi-nation of the total antioxidant power with the use of Expert-006 coulometer in galvanostaticmode confirms high antioxidant power of all Chinese green tea samples.The lack of fermentation process which is the important part in black tea production gives the possibility for green tea to preserve all polyphenol compounds and water-soluble vitamins which prevent from peroxidation of cell membrane lipids.