Natural, tough and pH-responsive ultrasound modified soy protein isolate-arabinoxylan based double network hydrogels for controlled nutrients release

In present study, a pH-responsive double network (DN) hydrogel composed of soy protein isolate (SPI) and arabinoxylan (AX) for encapsulating riboflavin as a model compound was successfully constructed using SPI extracted under ultrasonic conditions (400 W, 180 s) combined with AX. This study explored the impact of AX addition on physicochemical properties and formation mechanism of DN hydrogels. In addition, it's in vitro digestion behavior and the controlled release kinetics of riboflavin from hydrogels with different concentration of AX were investigated using fitted models. The results showed that the incorporation of AX significantly reinforced the hydrogel's mechanical strength, optimized its microstructure, and facilitated its hardness, cohesiveness, and elasticity. The synergistic network effect and dual cross-linking mechanisms between AX and SPI molecules were elucidated, showing the formation of interconnected, dual-continuous, and dense structures by chemical interaction forces, such as hydrophobic bonds and covalent bonds. Under simulated gastrointestinal digestion, the SPI-AX hydrogel, particularly at 1.0% (w/v) AX, demonstrated superior performance with high encapsulation efficiency, drug-loading capacity, and a pH-responsiveness, with a larger swelling ratio difference observed between SIF and SGF compared to SPI. The DN hydrogel exhibited a riboflavin release efficiency of 98.04%, with minimal lost in stomach. The release kinetics of drug fitted by Korsmeyer-Peppas model highlighted the hydrogel's responsive behavior to varying pH conditions in vitro, allowing for precise release control. This research emphasizes the advanced mechanical properties, structural refinement, and tailored release capabilities of the ultrasound-modified SPI-AX DN hydrogel as an effective riboflavin delivery matrix.