The working FRAP reagent was prepared daily by mixing 300 mM acetate buffer (pH 3.6), 20 mM ferric chloride, and 10 mM 2,4,6-tripyridyl-S-triazine in 40mM HCl in the ratio of 10:1:1 (v/v/v). The total phenolics extracted samples (300 μL) were added to 2.7 mL of the FRAP working solution incubated at 37 °C and vortexed.