Impact of dynamic high-pressure microfluidization on conformation and gel properties of peanut protein isolates

Abstract

The impact of dynamic high-pressure microfluidization (DHPM) (30–150 MPa) on the structure of peanut protein isolate (PPI) and PPI gel behavior and microstructural properties were studied. The research found that DHPM treatment significantly decreased the volume-mean diameter of PPI (p < 0.05), and induced the β-sheets, β-turn and random coils to transform into α-helix structures. With increased pressure, the hydrophobic groups of PPI were exposed to the outside, thus the surface hydrophobicity of PPI enhanced, and the sulfhydryl content and disulfide bond content increased significantly (p < 0.05) compared to control samples. Furthermore, the hardness of MTGase-induced gel increased gradually from 0.14 N (0.1 MPa) to 0.35 N (150 MPa). And the water-holding capacity of PPI gel reached its maximum at 90 MPa. The types of intermolecular interactions in the PPI gel were mainly hydrophobic interactions and disulfide bonds. Gʹ and Gʹʹ increased significantly from 30 MPa to 90 MPa. The microstructure of the gel systems upon 90 MPa and 120 MPa treatment showed more optimal surface appearance. These results indicate that the DHPM treatment could provide a new way to enhance the gel properties of PPI.