Investigating the effect of brewing additives on the antioxidant activity of black tea

Black tea is the most important beverage, which is consumed alone or with different additives. The present study tries to investigate the effect of different concentrations (0.5, 1, and 2 g) of some brewing additives (clove, cinnamon, coriander, saffron, and ginger) on the antioxidant activity of black tea. Total antioxidant capacity, total phenols, and flavonoid compounds were measured respectively, by FRAP, folin ciocalteu, and aluminum chloride colorimetric methods, for fresh tea extracts and with different additives. As the result of addition of different concentrations of these additives to black tea, maximum total antioxidant capacity (9067.36 µmol/L FRAP ) was observed by adding 2 g of clove to tea and the maximum polyphenols compounds was gained by adding 0.5gr clove (1894.66 mg Galic acid/L) and 0.5 ginger (1844/66 mg/L) to black tea, respectively. In addition, the maximum total flavonoid compounds content was gained by adding 2 grams saffron (728.93 mg quercetin/L) and 0.5 grams clove (678.16mg/ L) to black tea, correspondingly. Tea is a proper source of natural antioxidants supply for body, on behalf of its phenolic and flavonoid compounds, and adding the additives used in this research resulted in an increase in antioxidant activities of black tea. Totally, the effect of adding clove on the antioxidant properties of black tea was more effective than other additives.