2.4. Antioxidant properties
Sample extraction protocol for antioxidant analysis was the
same as for total phenolics. The antioxidant capacities were
expressed as m mol trolox equivalent (TE)/g db.
2.4.1. ABTS assay
The ABTS (2,20-Azino-bis(3-ethylbenzothiazoline-6-sulfonic
acid) diammonium salt) antioxidant activity was determined using
ABTSþ radical cation decolorization assay (Re et al., 1999), with
little modification. Briefly, 7 mmol/L ABTS solution and 2.45 mmol/
L potassium persulfate were mixed in 1:1 ratio and allowed to stand
in the dark for 12e16 h to produce ABTS radical cation (ABTSþ)
stock solution. The ABTSþ working solution (3 mL) and 30 mL of
blank, standard or sample were mixed and the absorbance was
measured at 734 nm after 6 min using a spectrophotometer. The
blank was run with methanol-80 and standard curve was prepared
using 0.3e1.5 mmol Trolox/L.
2.4.2. DPPH assay
Radical scavenging activity of mango powders was determined
following Brand-Williams, Cuvelier, and Berset (1995).