2.8. In Vitro Antioxidant Activities

The free radical scavenging (DPPH and ABTS) assays and ferric reducing antioxidant power (FRAP) assay were performed according to the methods described by Espín et al. [30], with slight modifications. The measurements were performed at microscale using 96-well microplates and measured by a Multiscan FC microplate reader (Thermo-Fisher Scientific, Inc., Waltham, MA, USA). In DPPH and ABTS assays, 12 µL of bean extract were added to 188 µL of working solution to complete the volume reaction of 200 µL. The absorbance was measured at room temperature after 30 min of reaction at 520 nm for DPPH and at 734 nm for ABTS. In the FRAP assay, the total reaction volume was 300 µL, corresponding to 12 µL of bean extract and 288 µL of working FRAP solution. The mixtures were incubated for 30 min at 37 °C in the dark and read at 593 nm. The results of all procedures were measured as µM of trolox equivalents per gram of dry weight (µM TE/g dw).