In vitro and in vivo antioxidant capacity of chia protein hydrolysates and peptides

The industrial production of chia oil is carried out by cold extraction of the seed. This process generates residues, the by-product, currently used in the manufacture of defatted chia flour and animal feed, being a low cost product. The objective of this study was to hydrolyze proteins from the by-product of chia oil and to obtain peptides with antioxidant properties. Chia flour by-product (CF), a protein-rich fraction (PRF), and chia protein concentrates (CPC1 and CPC2) were hydrolyzed with Flavourzyme (F), Alcalase (A), and a sequential system (S). The hydrolysates were then ultrafiltered, obtaining the fractions F1 (> 10 kDa), F2 (3-10 kDa), and F3 (< 3 kDa). The antioxidant capacity was measured in the hydrolysates and in the peptide fractions. Peptides corresponding to CPC1-F3 and CPC2-F3 fractions displayed the best antioxidant properties, although those of CF-F2 and PRF-F2 were also good. The Flavourzyme-generated hydrolysates were superior antioxidants, followed by those prepared with Alcalase. CPC2-S F2 (500 mu g g(-1)), CF-S F3, CF-A F3 and PRF-A F3 fractions in concentrations of 250 and 500 mu g g(-1) presented the best action against the lipid oxidation in a model meat system, indicating the possible efficacy of these peptides as antioxidants in food products. Furthermore, CF-S F3, CPC2-F F2, CPC1-A F2, and CPC1-F F2 significantly increased Saccharomyces cerevisiae survival when exposed to hydrogen peroxide. In conclusion, protein hydrolysates from the by-product of chia oil production have potential in vitro and in vivo antioxidant capacity and can effectively inhibit lipid oxidation in food models.