Enzymatically hydrolyzed soy protein nanoparticle-polysaccharide composite hydrogels for enhanced stability and pH-responsive release of fucoxanthin.

Abstract

Fucoxanthin (FX), a hydrophobic marine carotenoid, exhibits low stability and oral bioavailability under harsh conditions. A pH-responsive sodium alginate-xanthan gum (SA/XG) hydrogel incorporating soy protein nanoparticles (SPN) was fabricated for FX stabilization and intestinal-targeted release. SA/XG ratio and intermolecular interactions govern its physicochemical performance. The optimal hydrogel was formulated with SPN obtained after 1.5 h of enzymatic hydrolysis, 1.5% (w/v) sodium alginate, and 1.5% (w/v) xanthan gum at an SA/XG volume ratio of 2:1. It exhibited an encapsulation efficiency of 78.47 ± 2.11%. In vitro digestion resulted in minimal FX release in simulated gastric fluid, whereas 83.85 ± 1.01% of FX was released in simulated intestinal fluid. The Korsmeyer-Peppas model indicated that the release was primarily governed by hydrogel swelling and Fickian diffusion. SPN/FX/SA/XG hydrogel extract showed >90% HaCaT cell viability (negligible cytotoxicity), enabling efficient FX encapsulation and sustained release for oral-food use.