Protein fibering combined with a composite network strategy to enhance the soybean protein-sodium alginate hydrogel

A composite network hydrogel was prepared using soybean protein amyloid fibrils (SPAF) and sodium alginate (SA) through Ca²⁺ induction. The influence of Ca²⁺ on the microstructure and rheological properties of the SPAF-SA hydrogel was investigated. The results confirmed the successful preparation of SPAF, as verified by Thioflavin T fluorescence, X-ray diffraction (XRD), and Atomic Force Microscope (AFM). Microstructural analysis revealed that the SPAF and SA interacted via hydrogen bonds, with SA crosslinked by Ca²⁺ to strengthen the structure, resulting in a compact 3D network within the SPAF-SA hydrogel. Rheological testing demonstrated the elasticity and viscosity changes of the hydrogel under shear stress, and revealed the role and structural transitions of the composite network structure. Additionally, Ca²⁺ significantly influenced the strength of the hydrogel, with the SPAF-SA hydrogel exhibiting maximum strength at a Ca²⁺ addition of 1.2% (w/v). The findings highlight the potential of the SPAF-SA hydrogel as a food texture enhancer, offering insights into its practical applications in hydrogel systems.