Determination of tamin, caffeine and their antioxident capacity of extract from commercial green tea products in Lam Dong +CD

Abstract

Fifteen different green tea products (BongHong, ThienHuong, TamChau, LamBinhMinh, NganGiang, NgocTrang, ThuanAnhHoa, HongThai, RongVang, TramAnh, DoHuu, LongVan, BaoTin, HuongKimThao, ThanhNgoc) sold in BaoLoc city, LamDong province. We measured and compared the total phenolic compound, and caffeine by spectrophotometry, the content of tannins by titration. In addition, the antioxidant activity of the infusions was determined by spectrophotometry. NganGiang brand and DoHuu brand showed better antioxidant and total phenolic compound. The results obtained have shown that the caffeine content was relatively high in all tea sample and ranged from 143 ± 2.65 (mg/g) in HuongKimThao brand to 354.3 ± 2.65 (mg/g) in ThanhNgoc brand. The tannin content was low generally and ranged between 180.8 ± 0.68 (mg/g) in BongHong to 257.7 ± 0.98 in ThanhNgoc brand. Key words: Total phenolic compound Caffeine Tannin Antioxidant contents Green Tea