Soy Glycinin as a Natural Cross-Linker to Promote Sustainable Plant–Animal Hybrid Protein Aggregation

Strategic regulation of protein coaggregation via molecular interactions enables sustainable production of gel-based foods with reduced economic and ecological effects. This study explored the synergistic effect of soy glycinin (11S) on the heat-induced aggregation of cod proteins (CPs), focusing on aggregate formation pathways and molecular interactions. Incorporation of 11S restructured the secondary structure of CPs with increased β-sheet content, which facilitated coaggregation and produced large-sized complexes with low molecular weight. At 100 °C, the dissociated basic subunit of 11S preferentially bound to myosin heavy chains and actin, triggering further assembly through hydrophobic interactions and disulfide linkages, with hydrophobic forces being dominant. Moreover, acidic pH and salt ions contributed to synergistic enhancement in the coaggregation behavior, with Ca²⁺ inducing additional cross-linking between proteins via actin-binding sites. These findings highlight 11S as a native, sustainable cross-linker to enhance CP aggregation, fostering the engineering advances of clean-label hybrid protein foods.