Antimicrobial peptide NP-6-loaded chitosan nanoparticles for the preservation of chilled pork

This study reports the development of chitosan nanoparticles loading antimicrobial peptide NP-6 (NP-6-CS NPs) for meat preservation. The peptide NP-6 was encapsulated into a chitosan (CS) matrix using ionotropic gelation. The optimal conditions were as follows: CS:NP-6:TPP mass ratio of 6:3:2, CS concentration of 1 mg/mL, and reaction time of 30 min at pH 4.8. Under these conditions, the encapsulation efficiency (EE), particle size, polydispersity index (PDI), and zeta potential were 48.03%, 137.53 nm, 0.39, and 21.43 mV, respectively. Transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry analyses confirmed the successful loading of NP-6. The NP-6-CS NPs exhibited potent antibacterial activity against both Staphylococcus aureus and Escherichia coli , with a minimum inhibitory concentration (MIC) of 75 μg/mL. When applied to chilled pork, NP-6-CS NPs effectively maintained the meat’s color and inhibited spoilage indicators such as pH, volatile basic nitrogen, and total viable counts. These findings suggest that NP-6-CS NPs have significant potential as a novel, natural preservative to extend the shelf life of chilled pork. • NP-6 was encapsulated within CS-TPP NPs via the ionic gelation method. • NP-6-CS NPs showed enhanced antibacterial activity. • NP-6-CS NPs effectively suppressed key spoilage indicators in chilled pork.