BACKGROUND: Oxidative reactions are responsible for the changes in quality during food processing and storage. Oxidative stress is also involved in multiple chronic diseases, such as cardiovascular and neurodegenerative disorders, diabetes, cancer, and aging. The consumption of dietary antioxidants has been demonstrated to help to reduce the oxidative damage in both the human body and food systems. In this study, the potential of Erythrina edulis (pajuro) protein as source of antioxidant peptides was evaluated.RESULTS: Pajuro protein concentrate hydrolyzed by alcalase for 120 min showed potent ABTS ·+ and peroxyl radical scavenging activity with Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) values of 1.37 ± 0.09 mol TE mg −1 peptide and 2.83 ± 0.07 mol TE mg −1 peptide, respectively. Fractionation of the hydrolyzate to small peptides resulted in increased antioxidant activity. De novo sequencing of most active fractions collected by chromatographic analysis enabled 30 novel peptides to be identified. Of these, ten were synthesized and their radical activity evaluated, demonstrating their relevant contribution to the antioxidant effects observed for pajuro protein hydrolyzate. CONCLUSIONS: The sequences identified represent an important advance in the molecular characterization of the pajuro protein, demonstrating its potential as a source of antioxidant peptides for food and nutraceutical applications.
Oxygen radical absorbance capacity (ORAC) assayThe oxygen radical absorbance capacity (ORAC) was determined following the protocol described by Hernández-Ledesma et al. 26 The final assay mixture (200 μL) contained FL (30 nmol L −1 ), AAPH (12 mmol L −1 ), and antioxidant (Trolox (0-5 nmol L −1 ) or sample J Sci Food Agric 2019; 99: 2420-2427
Identification of antioxidant peptidesFraction UF-3, containing peptides < 3 kDa, was selected for further purification. The different fractions collected by elution wileyonlinelibrary.com/jsfa