Effect of Brewing Temperature on the Total Antioxidant Capacity of Green Tea

Abstract

The relationships between the total available antioxidant capacity of green tea and the brewing temperature and preparation time were studied, with the Trolox equivalent antioxidant capacity (TEAC) assay used to determine the antioxidant levels. The initial green tea mass-to-water volume ratio was set to 10 g/L, %-inhibition values were determined at various concentrations through serial dilution, and the slope of the relationship between %-inhibition and concentration was used to determine the TEAC value. The total antioxidant capacities of green tea determined under the experimental conditions adopted in this study are in the 214-819 μmolTrolox/ggreen tea range, which is significantly higher than previously reported values for various common fruits and vegetables. The total available antioxidant capacity was found to increase with temperature at a rate of approximately 6 (μmolTrolox/ggreen tea)/°C when brewed for 4 min. Green tea concentration, brewing time, and brewing temperature were experimentally determined to be the primary factors that determine the antioxidant capacity.