Analysis Of Effective Biological Components In Chinese Commerical Tea Drinks

For thousands of years, tea is very popular in the world. China is a big country which produces and consumes teas. There are various components which have benefits for people's health in the tea, such as polyphenols, amino acids, and carbohydrate. A lot of biological functions, such as anti-oxidation, anti-cancer and anti-allergy, have been attributed to the presence of the effective biological components from tea. Nowadays, the market of Chinese tea drinks is developing so fast that there are more and more kinds of tea drinks have appeared, but the quality of these products are different.Because the physical and chemical items of the national standards were not complete, and the methods of detecting were very complicated, in this study, four kinds of effective biological components—polyphenols, amino acids, caffine and carbohydrate, in ten kinds of different commercial tea drinks had been detected and analysised, Colorimetric technique and HPLC were used to determine and quantitate those components, and compared with the physical and chemical items of the national standards and the former ingredient table of these products.Major research results were followed:1. The results of the colorimetry using iron tartrate and chloroforms shoewd that, the tea drinks which were made of the tea power or the concentrated tea juice had lower consentration of tea pplyphenols and caffine, which of three kinds were lower than the ones of national standards; the results of HPLC show that only one kind of tea drinks had less caffine than that of national standards, howerer, about the consentrations of the major catechins in the the tea drinks which were made of the tea power or the concentrated tea juice were also lower;2. Using the ninhydrin colorimetry, the amino acids in tea drinks had been analysised; by using precolumn derivatization with o-phthaladehyde combined with HPLC, theanine in tea drinks had been determinated and quantitated. Comparing the contents of amino acids and theanine. it demonstrated that theanine was more than 50% of amino acids in the tea drinks; by comparing the differents kinds of tea drinks, the ice tea drinks had lower consentrations of amino aicds and theanine, which may be attributed to the producing technology; 3. The contents of total carbohydrate in the ten kinds of tea drinks had been determined by using phenol vitriolic colorimetry and the kinds of carbohydratehave been determinated and quantitated. The results of phenol vitriolic colorimetry demonstrated that there were no obvious difference between the low-carbohydrate and normal kinds, howere the results of HPLC showed that the total contents of carbohydrate in the low-carbohydrate kinds were less than 4000mg/kg. Maltose was found in the only kind which added honey while fructose and glucose were found in four kinds of tea drinks when there was only one kind of product had invert syrupin the ingredient table.