Influence of High-Pressure Processing and Microbial Transglutaminase on the Properties of Pea Protein Isolates

This study investigated the effects of high-pressure processing (HPP; 600 MPa/15 min) and microbial transglutaminase-catalyzed (MTG; 30 U·g of protein−1) crosslinking on the concentration of dissolved proteins (SOL), free sulfhydryl groups (SH), surface hydrophobicity (H0), and viscosity of pea protein isolates (PPI) at different concentrations (1–13%; w/v). The SOL increased by increasing protein concentration (max. 29%). MTG slightly affected SOL. HPP decreased SOL with increasing protein concentration, and the combination MTG + HPP resulted in a lower SOL than HPP alone. The concentration of SH in untreated PPI increased with increasing protein concentration, reaching a maximum of 8.3 μmol·mg prot−1. MTG increased SH at higher protein concentrations. HPP lowered SH, but its concentration increased by increasing protein concentration. HPP + MTG offset the effect of MTG, yielding lower SH. MTG did not affect H0 at 1% concentration but increased it for concentrations from 3–5%, and there was a decrease with 7–9%. HPP increased H0 up to 37% for intermediate protein concentrations but did not affect it at higher concentrations. MTG + HPP decreased H0 at all protein concentrations. The viscosity of the dispersions increased with protein concentration. HPP increased the viscosity of the dispersions for concentrations above 7%, while MTG only caused changes above 9%. Combined MTG + HPP resulted in viscosity increase. The results underscore the opportunity for innovative development of high-protein products with improved properties or textures for industrial application.