Effect of high-pressure jet processing on the structure and physicochemical properties of plant protein isolate aqueous dispersions

There is a strong interest in incorporating proteins from plant sources into protein-rich beverages. However, the use of protein isolates in food systems is restricted by their poor solubility and overall functionality. This research aimed to investigate the impact of high-pressure jet (HPJ) processing from 0 (control) to 500 MPa on the structural and physicochemical properties of three commercial soy protein isolates (SPIs) and pea protein isolates (PPIs) 5% w/v aqueous dispersions. Processing by HPJ at 100 MPa caused a strong dissociation of large protein bodies into smaller protein aggregates, following by a linear reduction in particle size when processing from 100 to 500 MPa. Native-PAGE of the supernatants showed that the molecular weight of the obtained soluble fractions was >250 kDa (no monomeric units), indicating the lack breakdown of protein covalent bonds. The reduction of the large protein bodies into small-size protein aggregates affected the overall functionality of the protein isolates. The solubility and the foaming capacity of plant proteins increased >15% as the aggregates dropped in size due to HPJ processing. The hydroxyl radical scavenging activity of PPIs increased >15% after pressurization, but HPJ did not influence the emulsion stability. The improvement in the physicochemical properties of plant-based proteins highlights the potential use of HPJ technology to create novel ingredients that feature clean label claims.