Effects of amyloid fibrils and divalent ions on the structure, rheological behavior, and gel properties of potato protein/carboxymethyl chitosan hydrogels.

Plant protein-based hydrogels have attracted increasing attention, but the poor gel-forming ability of native proteins limits their applications. In this study, potato protein (PP) amyloid fibrils (PFs) with different fibrillation degrees were prepared by regulating the initial protein concentration and incorporated with carboxymethyl chitosan (CMCS) and divalent ions (Zn2+ or Mg2+) to construct composite hydrogels. The results showed that moderately fibrillated PFs promoted β-sheet formation, strengthened intermolecular interactions, and facilitated a denser three-dimensional network, thereby improving water-holding capacity, viscoelasticity, and structural stability. Excessive fibrillation induced PF aggregation and fibril bundle formation, limiting network construction. Compared with Mg2+, Zn2+ promoted stronger crosslinking, resulting in enhanced gel strength, springiness, and thermal stability. These effects were associated with the synergistic interactions among PP, PFs, and divalent ions. This strategy converts PP into structurally reinforcing PFs and enables its integration into high-performance hydrogels, providing a promising approach for the value-added utilization of PP.