Effects of extrusion treatment on the physical and emulsifying properties of wheat germ protein

Abstract This study investigated the impact of the extrusion of defatted wheat germ (DWG) on the physical properties of wheat germ protein (WGP) and its efficacy as a novel emulsifier in terms of emulsion stability. Compared with the untreated sample, the particle size of extruded WGP (E-WGP) was decreased by 56.22 %, while the absolute zeta-potential was increased by 40.07 %; the enthalpy increased from 0.013 J/g to 0.078 J/g, and the structure became more orderly. The amount of protein required to produce stable emulsions was much lower for E-WGP than for untreated WGP. Moreover, The E-WGP emulsions showed good storage stability after 7 day of storage at 4 °C, which had higher absolute zeta-potential (24.65 %), emulsifying activity (200.00 %), and turbidity (139.09 %) than the untreated sample. After the freeze-thaw cycle, the E-WGP emulsions had smaller particle sizes and higher turbidity, and their flocculation degree was lower than that of the untreated sample. These findings demonstrate E-WGP can be used as a new innovative emulsifier.