Work

Pressure effects on structure–function properties of dry-fractionated pea proteins under high-pressure homogenization

Year: 2025

Type: article

Abstract: • Equal-energy high-pressure treatments applied on dry-fractionated pea proteins • Polysaccharide matrix shields proteins from major structural modifications • Higher pressures improved solubility without enhancing gelling capacity • Starch granules were damaged under high-pressure treatments • Processing pressure influences pea protein structure and functionality This study investigated the impact of high-pressure homogenization (HPH) on the structural and techno-functional properties of a dry-fractionated pea protein concentrate, focusing on pressure–cycle combinations delivering equivalent energy densities (90 MJ/m³). Suspensions (6% w/w) were treated at 15 MPa × 6 cycles, 22.5 MPa × 4 cycles, and 45 MPa × 2 cycles, then analyzed for molecular, physicochemical, and gelling properties. SDS-PAGE, free sulfhydryl groups quantification, intrinsic fluorescence, and FTIR spectroscopy revealed no major structural changes, but indicated pressure-dependent exposure of hydrophobic groups and minor tertiary rearrangements. Particle size distribution and ζ-potential measurements demonstrated significant reduction of insoluble particle dimensions, with evidence that the polysaccharide matrix, particularly starch, exerted a protective effect on protein conformation. Techno-functional characterization showed that solubility at pH 7 enhanced at higher pressures despite constant energy input, attributable to increased surface hydrophilicity. Surface tension was unaffected, suggesting limited changes in interfacial properties. Rheological analyses revealed formation of weak gels with reduced structural strength at higher pressures, likely due to disruption of protein–polysaccharide interactions and starch granule damage, as confirmed by confocal and optical microscopy. Overall, while equal-energy HPH treatments produced distinct pressure-driven modifications in dispersion characteristics and solubility, they did not enhance gelling capacity. The results highlighted the role of the polysaccharide fraction in modulating HPH-induced protein changes and underscore the importance of tailoring processing parameters to optimize functionality in sustainable, minimally processed plant protein ingredients.

Source: Applied Food Research

DOI: 10.1016/j.afres.2025.101488