Abstract:Quinoa was used as raw material for the extraction of protein isolate and separation of component proteins (albumin，globulin，and glutenin) by alkaline solubilization-acid precipitation and Osborne grading methods，respectively.The physicochemical properties such as thermodynamic properties，secondary structure，and molecular weight distribution，as well as the functional properties such as emulsification properties，foaming ability，and water-and oil-holding properties were determined.The results showed that the subunit bands between 20 kDa and 50 kDa of the four proteins were significantly different in reducing and non-reducing electrophoresis modes.Quinoa glutenin had higher thermal stability.Fourier transform infrared spectroscopy confirmed the significant differences in the secondary structures among different proteins.Glutenin had a high amount of disulfide bonds and a moderate amount of free sulfhydryl groups.Globulin had higher surface hydrophobicity.The solubility of the proteins showed typical U-shaped curves with changes in pH.Especially，the solubility characteristics of the protein isolate were the most significant.In addition，quinoa isolate had the best water holding and emulsifying properties.Quinoa globulin had the best oil-holding properties.Quinoa albumin had excellent foaming ability.