Dual-induced sorghum bran arabinoxylan and soy protein isolate composite gels: Insights into their formation and application as bioactive component delivery carriers

Sorghum bran arabinoxylan (AX)-soy protein isolate (SPI) composite gels were fabricated via a dual-induction strategy, in which peroxidase was used for AX covalent cross-linking and Ca 2+ for SPI ionic cross-linking. These composite gels were evaluated as delivery vehicles for bioactive compounds, with cyanocobalamin used as the model nutrient. The effects of AX:SPI mass ratio on gel properties and cyanocobalamin release behavior were systematically investigated. Gel's mechanical strength first increased then decreased with rising SPI proportion, and the 1:1 AX:SPI gel exhibited the optimal performance, which was characterized by the highest hardness, and a regular, homogeneous network with thick pore walls. In vitro digestion experiments confirmed that, unlike single-component AX gels where cyanocobalamin release was dominated by swelling-driven diffusion, the 1:1 AX-SPI gel mediated cyanocobalamin release via the synergistic effect of matrix erosion and swelling diffusion. This release mechanism reduced cyanocobalamin release in simulated gastric fluid and enhanced its release in simulated intestinal fluid. This study demonstrated that the dual-induction strategy enabled the fabrication of AX-SPI composite gels with tailored network structures, and the 1:1 formulation showed significant potential for application in targeted intestinal nutrient delivery systems. • AX:SPI ratio regulated strength and network of dual-induced composite gels. • 1:1 composite gel had high hardness, thick pore walls and regular microstructure. • Cyanocobalamin release from AX gel was dominated by swelling-driven diffusion. • Cyanocobalamin release from composite gels was mediated by erosion and swelling. • 1:1 gel showed huge potential as delivery vehicles for Cyanocobalamin.