FRAP RADICAL SCAVENGING CAPACITY OF GREEN TEA, OOLONG TEA, AND JEJU FERMENTED TEA BY PRODUCED PRODUCTS

Man Kyu Huh*

ABSTRACT

Tea (Camellia L.) is one of oldest, non-alcoholic and caffeine-containing beverage or medicine in world community. This study determined antioxidant activity in terms of the ferric reducing antioxidant power (FRAP) of commercial tea products, i.e., green tea, oolong tea, black tea, and Jeju fermented tea. Jeju fermented tea was showed the highest inhibition activity of FRAP among four groups. There was a significant difference among all concentration levels (p < 0.05 and 0.001). When the BHA used as a control, relative FRAP scavenging activities of green tea, Oolong tea, black tea, and fermented tea were 77.4%, 83.7%, 88.7%, and 104.2, respectively. The antiradical activity analysis permitted classifying tea extracts in medium activity group. The sample concentration providing 0.5 of absorbance (IC50) of green tea, Oolong tea, black tea, and fermented tea were 61.4 μg/ml, 52.1 μg/ml, 57.9 μg/ml, and 48.5 μg/ml, respectively. The mode of inhibition of the tea extracts against FRAP was competitively inhibited FRAP by Lineweaver–Burk plots. In the processing of tea, fermentation plays an important role in determining the quality of Jeju tea.

Keywords: Ferric reducing antioxidant power (FRAP), Jeju fermented tea, Lineweaver–Burk plots.