# Antioxidant Activity and Resistance Against Oxidation of Peptide Fractions from Common Bean (Phaseolus vulgaris L.) Landraces Assessed by EPR and Chemical Assays

## TL;DR

This study identifies antioxidant peptides from common bean landraces, showing their potential as functional food ingredients.

## Contribution

The study introduces a novel characterization of antioxidant peptides from common bean landraces using multiple in vitro assays.

## Key findings

- Peptides < 3 kDa showed higher antioxidant activity in DPPH, FRAP, and ORAC assays.
- Landraces like Apolo, Magnum, Boloto, and Hallado exhibited particularly high antioxidant potential.
- Common bean-derived peptides demonstrate resistance against oxidation and multiple antioxidant mechanisms.

## Abstract

The objective of this study was to obtain and characterize bioactive peptides derived from common bean (Phaseolus vulgaris) landraces and to evaluate their antioxidant potential using multiple in vitro assays. Protein isolates were obtained by isoelectric precipitation followed by enzymatic hydrolysis using Alcalase. Peptides were separated by ultrafiltration into fractions < 3 kDa and 3–10 kDa, yielding a total of forty samples. Antioxidant activity was evaluated using DPPH, FRAP, and ORAC assays. Antioxidant responses ranged from 13.06 to 50.8% inhibition in DPPH, 52.2 to 1750 µmol TE/100 g in FRAP, and 305 to 5246 µmol TE/100 g in ORAC. Resistance against oxidation ranged from 10.6 to 68.8%. Peptides < 3 kDa generally exhibited higher antioxidant activity in the functional assays, particularly in the Apolo, Magnum, Boloto, and Hallado landraces, although some 3–10 kDa fractions also showed relevant activity. Peptide extraction yields ranged from 3.73 to 10.39% and from 1.33 to 4.74%, while soluble protein contents ranged from 23.1 to 460 and from 9.9 to 288 mg BSA/100 g beans for <3 kDa and 3–10 kDa fractions, respectively. Overall, the results support the potential of common bean-derived peptides as functional food ingredients with antioxidant activity mediated through multiple mechanisms.