Physicochemical, conformational and functional changes of quinoa protein affected by high-pressure homogenization

Abstract

High-pressure homogenization (HPH) (30, 60, 90,120, and 150 MPa) effectively influenced the physicochemical, conformation, and functional changes of quinoa protein suspensions. The solubility of quinoa proteins increased from 6% to 52% with HPH treatment up to 120 MPa and obtained a maximum value (43.73 mV) in absolute zeta potential. The turbidity and particle size of the quinoa protein decreased with the increasing homogeneous pressure. HPH treatment at 120 MPa increased emulsion activity index (21 m2/g), foaming capacity (104%) and surface hydrophobicity (36.5 μg) than HPH treatment at varying pressures (30, 60, 90, and 150 MPa). HPH treatment decreased intrinsic fluorescence, exposing tryptophan residues and changing the tertiary structure of quinoa proteins. Fourier transform infrared spectroscopy (FTIR) showed that HPH treatment increased β-sheets and reduced α-helix and β-turn structure. Moreover, HPH altered the static rheological characteristics of quinoa protein by decreasing shear stress and viscosity. It also modified the thermal stabilities of quinoa protein by increasing its thermal denaturation temperature. HPH treatment has the potential to modify the functional properties of quinoa protein for industrial food applications.