2.8. Antioxidant activity
The free radical-scavenging activity, i.e., antioxidant activity,
of the optimized extract (unfiltered), permeates and
concentrates was determined by using DPPH (2,2-diphenyl-
1-picrylhydrazyl) according to the method of Brand-Williams
et al., 1995 modified by Sanchez-Moreno et al. (1998). One hundred
microliters of each sample were added to 3.9 mL of DPPH
methanol solution (60 M) and then transferred to a quartz
capillary. The color changed from purple to yellow and its
absorbance