However, it can be seen amongst
3 rice varieties in the present study that antioxidant
activity values determined by FRAP method were
not distinctive as those found by TEAC, which could
be due to different mechanisms involved. Trolox
equivalent antioxidant capacity has become routine
practice in evaluating antioxidant activity of plant
material due to its simplicity of the assay and the
fact that it can be used in aqueous and lipid phases
(Sompong et al., 2011). On the contrary, the principle
of FRAP assay is based on the reduction of the Fe(III)-
TPTZ complex to the ferrous form at low pH. This
reduction is monitored by measuring the absorption
change at 595 nm (Benzie and Strain, 1999).