[Antioxidant capacity of byproducts from amaranth (Amaranthus hypochondriacus) seeds]

The antioxidant capacity (CA) of byproducts from amaranth (Amaranthus hypochondriacus) seeds from two harvest parcels as a function of three extraction methods and two solvents was evaluated. On a first stage the effect of extraction method (homogenization, low frequency ultrasound, or the combination homogenization-ultrasound) and extraction solvent (methanol or ethanol, 100%) were evaluated; on a second stage, the effect of extraction solvent concentration (100%, 70%, or 50%) was evaluated. CA was determined by DPPH• inhibition, which was expressed as mg Equivalents of Trolox (ET)/g dry matter (DM). Total Phenolic compounds (FT) were determined by means of the FolinCiocalteu assay and expressed as Equivalents of Gallic Acid (EGA)/g DM. Antioxidant compounds were identified by gas chromatography coupled to mass spectrometry. For CA, there was not significant difference (p>0,05) among extraction methods, but there was significant difference (p<0,05) between solvents (3,39 and 1,28 mg ET/g DM, with methanol and ethanol, respectively). For FT, there was not significant difference (p>0,05) between solvents when they were diluted, but a significant difference (p<0,05) was observed when they were used at 100%. For CA, there was a significant (p<0,05) effect of solvent concentration, both studied solvents at 50% provided the best results (21,34 and 21,82 mg ET/g DM with methanol and ethanol, respectively). The qualitative analysis of the extracts exhibited the presence of squalene and 2,5-bis (1,1-dimethylethyl) phenol as the major compounds with antioxidant capacity.