Total Antioxidant Capacity of Teas by the Ferric Reducing/Antioxidant Power Assay

作者：Iris F. F. Benzie, Yim Tong Szeto · 发表于：Journal of Agricultural and Food Chemistry · 年份：1999 · DOI：10.1021/jf9807768 · 被引用次数：751 · 研究领域：Tea Polyphenols and Effects、Heavy Metals in Plants、Phytochemicals and Antioxidant Activities

This study aimed to compare in vitro antioxidant power of different types of tea (Camellia sinensis). The ferric reducing/antioxidant power (FRAP) assay was used to measure the total antioxidant power of freshly prepared infusions of 25 types of teas. Results showed that different teas had widely different in vitro antioxidant power and that the antioxidant capacity was strongly correlated (r = 0. 956) with the total phenolics content of the tea. Expressed as micromol of antioxidant power/g of dried tea leaves, values ranged as 132-654 micromol/g for black ("fermented") teas, 233-532 micromol/g for Oolong ("semifermented") teas, and 272-1144 micromol/g for green ("nonfermented") teas. One cup of tea of usual strength (1-2%), therefore, can provide the same potential for improving antioxidant status as around 150 mg of pure ascorbic acid (vitamin C).