High-Energy Electron Beam Irradiation-Induced Structural Changes Enhanced the Antioxidant Activity of Ovalbumin

Abstract

In this study, the typical ovalbumin (OVA) was chosen and exposed to high-energy electron beam irradiation (HE-EBI) at various doses (0, 25, 50, 75, 100 kGy) to survey the effect of HE-EBI on antioxidant activity of the protein. The results of reducing power, DPPH and ABTS + radical scavenging activities suggested that antioxidant activity of OVA exposed to HE-EBI were significantly improved ( P < 0.05). The ultraviolet absorbance, surface hydrophobicity as well as sulfhydryl groups were increased constantly, while the intensities of synchronous and intrinsic fluorescence were decreased in a dose-dependent paradigm. Meanwhile, fourier transform infrared spectroscopy and far-ultraviolet circular dichroism spectroscopy proved the blue shifts of amide I region and amide A band, the transformations from α -helix to other structures ( β -sheet, β -turn, and random coil) in OVA, respectively. Additionally, polyacrylamide gel electrophoresis showed that HE-EBI caused the disruption of various bonds including peptide bonds and disulfide bonds in OVA and modifications of amino acid residues. And a larger number of amino acids containing special groups such as indole and imidazole rings were found after HE-EBI treatment.   Conclusively, HE-EBI has a potential to be implemented as a "cold processing" technology to alter the structure and improve antioxidant activity of protein.

Keywords: Ovalbumin (OVA), High-energy electron beam irradiation (HE-EBI), Antioxidant activity, structure