Conformity assessment of product quality in the consumer market

Abstract

Among the traditional types of tea in the Russian market, Chinese Pu-erh tea has a special place. In the work, samples of Pu-erh tea presented on the market of Voronezh were investigated. The samples of black and green tea were compared. By mass fraction of moisture, water-soluble extractive substances, total ash, and the share of soluble ash, all tea samples met the standards. The amount of tannin in some samples of Pu-erh tea was low — 4.6–6.0% in NE; in terms of antioxidant activity (AOA), AOA, they were also inferior to black and green tea. A general positive correlation of tannin and AOA levels was noted. The fact that not all polyphenols have antioxidant properties is evidenced by the fact that the tannin content in tea samples differed by 7 times, AOA - by 3 times. To determine the antioxidant activity (AOA), we used the electrochemical titration method on an Expert-006 instrument in a cell with a background electrolyte — KBr in a H2SO4 solution; the marker is ascorbic acid. It is established that the method is simple, convenient; gives a relative error within 5%.