Sodium alginate-based hydrogel beads encapsulating curcumin-selenium nanoparticles for enhanced antioxidant, antimicrobial, and edible oil preservation.

Water-soluble antioxidants exhibit strong activity but limited effectiveness in edible oils due to poor lipid solubility and short residence time. In this study, a food-grade sodium alginate-chitosan hydrogel bead system encapsulating curcumin-loaded selenium nanoparticles (Cur@Se) was developed to enhance antioxidant delivery and stability in lipid matrices. The Cur@Se-loaded bead(chitosan concentration 5 mg/mL) formed a dense crosslinked network with improved mechanical strength (65% increase in hardness), high encapsulation efficiency (98%), and enhanced anti-swelling capacity (20%), enabling sustained release in the oil phase. This bead exhibited strong antibacterial activity against Staphylococcus aureus and Escherichia coli. Schaal oven tests demonstrated this hydrogel bead significant oxidative protection in soybean oil, reducing peroxide, acid value, p-anisidine, and total oxidation values by 31%, 39%, 33%, and 53%. Comparable protection was observed in rapeseed oil. This work highlights a food-grade, dual-functional delivery strategy integrating sustained release, interfacial antioxidant activity, and antimicrobial effects, providing a promising alternative to synthetic antioxidants for edible oil preservation.