2.9.2. Trolox equivalent antioxidant capacity (TEAC) assay

The ABTS radical cation (ABTS^•+) discoloration assay was performed according to Re et al. (1999) ​with some modifications. The ABTS^•+ was produced by reaction of ABTS (7 ​mM in water) with potassium persulfate (2.45 ​mM final concentration) in the dark at room temperature for more than 12 ​h. Prior to the assay, the solution was diluted in EtOH and equilibrated at room temperature to give an absorbance of 0.70 ​± ​0.02 ​at 734 ​nm. A Trolox standard curve (0–700 ​μM of Trolox/mL) was prepared in EtOH. Samples (20 ​μL, 0.1 ​mg protein/mL) were incubated for 6 ​min with 220 ​μL of ABTS^•+ radical cation solution before measuring absorbance at 734 ​nm. The TEAC was expressed as μM of Trolox equivalents/μg of protein.