Dual-functional CS-ZBP nanoparticles (CS-ZBP-NPs): Kinetic study of polyphenol release and synergistic antioxidant-antibacterial performance.

The development of natural, multifunctional nanomaterials is a promising strategy to replace synthetic preservatives in the food industry. In this study, Chitosan-Zanthoxylum bungeanum polyphenol nanoparticles (CS-ZBP-NPs) were successfully prepared via ionotropic gelation, with UV-Vis, FTIR, XRD, and XPS confirming covalent conjugation between chitosan and polyphenols. Electron microscopy revealed uniform spherical morphology and homogeneous dispersion. Thermal stability analysis showed enhanced resistance to decomposition compared to pure chitosan. The nanoparticles exhibited pH-responsive polyphenol release with sustained release under acidic conditions. Functional assays showed that CS-ZBP-NPs possessed strong antioxidant activity (90.35 % DPPH scavenging at 0.5 mg/mL), effectively inhibited lipid oxidation (47.6 % reduction in MDA formation) and protein oxidation (52.32 % reduction in carbonyl content), and exhibited broad-spectrum antibacterial activity against common foodborne pathogens, with a minimum inhibitory concentration (MIC) as low as 156.25 μg/mL against P. fluorescens. These enhancements are attributed to synergistic interactions between chitosan and ZBP, including covalent and hydrogen bonding. The findings underscore the potential of CS-ZBP-NPs as a bioactive nanomaterial for food preservation, addressing both oxidative degradation and microbial contamination.