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.