Abstract: Wheat germ protein (WGP) was extracted from wheat germ powder by alkali dissolution and acid precipitation, and WGP was modified by microwave and metal ion treatment. The functional properties, structure, and molecular mass of WGP before and after modification were determined. The results showed that compared with the control group, the solubility of WGP was increased by 86.61% after the combined treatment, the water-holding capacity (WHC) and oil-holding capacity (OHC) were increased by 22.86% and 82.16%, the emulsifying capacity, emulsion stability and foaming capacity were increased by 120.90%, 15.64% and 116.91%, respectively, and the foaming stability was reduced. The results of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that there was no significant change in the molecular mass of WGP after the combined treatment, while the structure became looser, and the secondary structure exhibited a trend toward a disordered state, mainly manifested as an increase of β-turn and random coil. The combined treatment was superior to either microwave or metal ion treatment alone in improving the functional characteristics of WGP. The combined treatment with microwave and metal ions offers WGP with good functional characteristics, thereby providing WGP the potential to be developed into a new functional food.

Key words: wheat germ protein; microwave; metal ions; functional features; structure