Elucidating the gelation mechanism of soy-potato protein composite gels: Proteomic, molecular, and structural...

The study investigated the gel properties and interaction mechanism of soy protein isolate (SPI) and potato protein (PP) composite gel. Results showed that increasing the proportion of PP could enhance the turbidity and surface hydrophobicity (H₀), facilitate the transition from random coil to β-sheet, strengthen both electrostatic and hydrophobic interactions, and decrease the disulfide bond content. This revealed that the interaction of the composite gel was enhanced after adding PP, and a more complex secondary structure was formed. Moreover, proteomic and electrophoresis analysis revealed that specific SPI subunits (P26987, Q96452, P02520, Q948P5, Q39839, P02580, P50346, and P69325) were irreversibly denatured in SPI/PP 70:30 composite gel, forming new protein segments (30-45 kDa and 70-90 kDa). Notably, SPI/PP 70:30 composite gel had the highest solubility, water-holding capacity (WHC), storage modulus (G') value, bound water content, gel strength and elasticity, while having a small average particle size and ζ-potential. The research results revealed the key role of SPI in maintaining the gel network and the significant enhancement effect of PP on protein cross-linking and gel properties. This finding helped to promote the more efficient and extensive application of plant protein in the food industry and other fields, and had important guiding significance for expanding the application scope of plant protein and improving product quality.