Cyclic voltammetry for antioxidant assessment of moth bean protein hydrolysates: a comparative study with spectrophotometric methods

The present study examined the functional attributes of whole moth bean (Vigna aconitifolia L.) seed extract upon gastrointestinal digestion (GI), along with other proteases viz. Alcalase and papain. Biochemical analysis revealed presence of highest phenolic and peptide content in papain hydrolysate. Spectrophotometric assays revealed enhanced antioxidant potential after hydrolysis, with < 3 kDa fractions consistently displaying superior antioxidant potential. GI digested hydrolysate demonstrated maximum ABTS+ radical scavenging and % iron chelation capacity. Cyclic voltammetric analysis affirmed the redox behavior observed in spectrophotometric assays and corroborated these findings. In both assays, < 3 kDa fraction (GF3) of GI digested hydrolysate showed highest antioxidant capacity with 34.9% ABTS radical scavenging and 72% iron reduction with the correlation coefficient of 0.86. Peptide sequencing of the < 3 kDa fractions revealed a high concentration of bioactive peptides in GF3, predominantly containing aromatic and hydrophobic amino acid residues, confirming its superior antioxidant potential. To the best of our knowledge, this study is the first to demonstrate a correlation between antioxidant activity assessed through biochemical assays and cyclic voltammetry. It also elucidated the enhancement of bioactivity of moth bean proteins upon GI digestion, underscoring the potential of the hydrolysate fractions in the development of functional foods with enhanced health benefits.