Effect of high hydrostatic pressure on solubility and conformation changes of soybean protein isolate glycated with flaxseed gum

Soybean protein isolate (SPI) was incubated with flaxseed gum (FG) at 60 degrees C for 3 days under high hydrostatic pressure (HHP 0.1-300 MPa). Results showed improvement in solubility of SPI upon glycation with FG. The maximum solubility reached 86.84% when SPI-FG was treated at pH 8.0 and 200 MPa. The occurrence, degrees and sites of SPI-FG glycation suggested that moderate pressure (100 MPa) significantly promoted Maillard reactions, but higher pressures (greater than 200 MPa) suppressed these reactions. The secondary structure of the glycated proteins varied greatly with respect to a-helix and random coil contents and vibrations of the amide II band at 200 MPa. These microstructural changes increased the solubility over a broad pH range. The conformational changes in the glycated SPI supported the improved solubility of SPI-FG. Overall, HHP represents a potential method of controlling glycation to improve protein processability and expand their applicability in the food industry.