2.2.5.2. Ferric reducing antioxidant power (FRAP). The FRAP
assay was performed according to the method described in previous
reports (Benzie & Strain, 1996) with slight modifications.
Briefly, the FRAP reagent was prepared using sodium acetate
buffer (300 mM, pH 3.6) supplemented with 10mMTPTZ, 40mM
HCl and 20 mM FeCl3 at a proportion of 10:1:1 (v/v/v).The FRAP
reagent was prepared fresh daily and warmed to 37 °C in a water
bath before use.Ten microliters of the tested sample were mixed
with 300 L of fresh FRAP reagent, and the absorbance at 593 nm
was recorded after 8 min. The standard curve was prepared
using Trolox solution (0.2–2 mg/mL), and the activity in the
samples was estimated as the Trolox equivalent antioxidant
capacity (TEAC) in mg/mL trolox/g. The structure–activity relationship
analysis of the samples and phenolics was performed
as mentioned in Section 2.2.5.1.