Structural modification of pea protein via high-energy fluidic microfluidizer: Mechanistic insights into enhanced solubility and acid-induced gelation properties

This study investigated the potential of a high-energy fluidic microfluidizer (HEFM) to enhance the solubility and gelation properties of pea protein. The effect of HEFM on the nitrogen solubility index (NSI) and structure of 10% pea protein suspension was investigated. HEFM treatment enhanced pea protein solubility, achieving a NSI of up to 98.51% at 280 MPa, which was a significant increase compared to the low NSI of untreated samples (18.01%). The treated proteins exhibited reduced particle size and increased specific surface area. Morphology analysis exhibited that the globular aggregates were dispersed by mechanical forces into loose and uniform protein particles, with the insoluble precipitate converting into soluble protein. Structural analysis revealed that HEFM treatment disrupted protein aggregates, increased surface hydrophobicity, and exposed free sulfhydryl groups. It also induced the secondary structure of the protein to change from β-sheets to α-helixes, contributing to improved solubility. Additionally, the gelling properties were positively correlated with increased protein solubility. The gels made from pea proteins with enhanced solubility exhibited denser, more homogeneous microstructures alongside higher storage moduli and greater cohesive strength. While demonstrating superior stability under LAOS deformation, the HEFM-treated PPG gels (pea protein-gellan gum gel) exhibited excellent stability. This study indicated that HEFM is an effective industrial-scale technique for improving the solubility and gelation of pea protein, thereby expanding its potential applications in the food industry.