Effects of electron beam irradiation pretreatment on the structural and functional properties of okara protein

The structural and functional properties of okara protein pretreated with electron beam irradiation (EBI) at different doses (0–10 kGy) were investigated. The results of Fourier transform infrared spectroscopy spectra and fluorescence spectra indicated that EBI treatment decreased the α-helix and β-sheet proportion, contributing to a less compact tertiary conformation, thereby increased the fluorescence intensity with a red shift of λmax. Scanning electron microscopy images indicated that okara protein was fragmented into smaller pieces and the surface was uneven with pores after EBI treatment. The solubility, thermal stability and emulsification characteristics of okara protein were regulated by modifying its structure by EBI treatment. When the EBI treatment dose was 6 kGy, the protein had the highest solubility, as well as emulsification characteristics. Taken collectively, these results demonstrate that EBI can improve the functional properties of okara protein, which may widen the application of the protein.