Selenium nanoparticle loaded on PVA/chitosan biofilm synthesized from orange peels: antimicrobial and antioxidant properties for plum preservation

Abstract

This study investigates the eco-friendly synthesis, characterization, and biological activity of selenium nanoparticles (SeNPs) incorporated into a polyvinyl alcohol/chitosan (PVA/CH) composite for antimicrobial, antioxidant, and food preservation applications. SeNPs were synthesized using orange peel extract as a reducing and stabilizing agent. Characterization through UV-Vis spectroscopy, FTIR, dynamic light scattering (DLS), TEM and zeta potential analysis confirmed the formation of stable, well-dispersed SeNPs. The antimicrobial activity of PVA/chitosan (PVA/CH) films incorporated with selenium nanoparticles (SeNPs) was evaluated against five pathogenic bacterial strains, showing a concentration-dependent enhancement, with the 1% SeNPs formulation achieving the highest inhibition zones across all tested pathogens. Se nanoparticles showed a more compact structure and excellent thermal and UV stability into PVA/CH-SeNPS film. Antioxidant potential was assessed using DPPH radical scavenging assays. The composites showed concentration-dependent free radical scavenging, with the highest activity observed at 1% SeNP concentration (IC50:45.2 µg/mL), closely approaching that of ascorbic acid (IC50: 38.6 µg/mL). HPLC analysis of orange peel extract identified high levels of rutin (546.46 mg/kg), quercetin (217.45 mg/kg), and chlorogenic acid (72.75 mg/kg), which likely contributed to the observed antioxidant properties. Cytotoxicity tests using Vero cells demonstrated high biocompatibility, with over 80% cell viability at all tested concentrations, confirming the composites’ potential for safe biomedical applications. Additionally, the use of PVA/CH-SeNP composites as an edible coating for Hollywood plum (Prunus domestica L. cv. Hollywood) was evaluated to extend postharvest storage. Fruits coated with 0.5% and 1% PVA/CH-SeNP showed significantly reduced weight loss (3.64% and 2.84%, respectively, compared to 6.91% in the control) and maintained higher firmness (7.20 N/cm² vs. 4.12 N/cm² in the control). The coatings also increased total soluble solids (TSS: 14.6°Brix), decreased acidity (0.936%), and enhanced L-ascorbic acid (19.86 mg/100 g) and anthocyanin content. These results highlight the potential of PVA/CH-SeNP composites as multifunctional biomaterials for antimicrobial, antioxidant, and food preservation applications. Future studies should explore their in vivo efficacy, long-term stability, and potential for large-scale applications.