The analysis was performed according to Benzie and Strain
(1996). The absorbance was measured at 593 nm using a Microplate
Spectrophotometer (Benchmark Plus, Biorad, Hercules, CA, USA),
using an aqueous solution of Trolox (0.25 mg/mL), at different concentrations
(0.1; 0.2; 0.4; 0.6 and 0.8 mM), as control. The ferric reducing
power was expressed as mmols Trolox equivalents/g DW.