Structural Modification and Enhanced Gel Properties of Peanut Protein via Co-Precipitation with Egg White Protein

Peanut protein (PP) is an abundant plant protein resource with limited gelation performance. In this study, the effects of co-precipitation with egg white protein (EWP) on the structural and gelation properties of PP were investigated. Structural analysis revealed that co-precipitation induced secondary structure rearrangement of PP, accompanied by decreased α-helix and β-sheet contents and increased random coil and β-turn contents. These changes were associated with the exposure of hydrophilic groups and the partial shielding of hydrophobic regions, contributing to the significantly improved solubility of PP-EWP co-precipitated proteins (p < 0.05). These structural changes were conducive to the formation of a denser and more continuous gel network. Compared with the PP gel, the gel prepared from PP-EWP co-precipitated protein at the PP:EWP ratio of 2:1 showed an increase in gel strength from 429.30 g to 911.94 g and in water holding capacity from 56.78% to 85.53%. This study provides a theoretical basis and practical guidance for improving the gel properties of PP through co-precipitation and developing functional peanut protein ingredients, although the relatively high cost of EWP should be considered in practical applications.