Mechanisms of the structures and antioxidant activity of broad bean protein affected by AC electric field: changes in conformation and molecular interaction

Abstract The hierarchical structure modification and antioxidant traits of broad bean protein (BBP) with low denaturation induced by alternating current electric field (ACEF) were examined. The ultraviolet, Fourier transform infrared, and Raman spectrometry showed that ACEF affected the tertiary and secondary structures of BBP, as evidenced by the significant increase in surface hydrophobicity, more β-turns and random coils, fewer β-sheets, and the variation of microenvironments of certain amino acid residues. X-ray diffractometry revealed that ACEF reduced the relative crystallinity and granular size of BBP, increased lattice spacing, caused the weakening of intermolecular forces, and significantly decreased the compactness of spatial conformations in BBP. Furthermore, the antioxidant capacity of BBP increased following ACEF treatment and was influenced by voltage. This may be due to the BBP structure unfolding and the release of aromatic amino acids.