The ABTS+ radical was generated by persulfate oxidation of ABTS by incubation at room temperature for at least 16 hours in the dark. An ABTS+ solution was diluted with 0.1 M phosphate buffer solution to absorbance values of 0.70 ± 0.02 at 734 nm. For measuring antioxidant capacity, 25 lL of the sample was added to 75 lL of the ABTS+ solution. The decrease in the absorbance was measured at 734 nm after 6 min