2.5. Determination of antioxidant activity
The antioxidant activity was measured by the ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid)) method performed as previously described (Pellegrini, Yang, & Rice-Evans, 1999). Briefly: 1 g of product were suspended in 10 ml of methanol; after centrifugation for 10 min at 2500g, 20 μl of supernatant were added to 1 ml of a solution containing the ABTS radical cation. The quenching of absorbance at 725 nm was compared with that obtained by a standard solution of Trolox. Antioxidant activity was expressed as mmol of Trolox equivalent for 100 g of product.