Mandarin (Citrus reticulata L.) essential oil incorporated into chitosan nanoparticles: Characterization, anti-biofilm properties and application in pork preservation

Mandarin (Citrus reticulata L.) essential oil (MEO) reportedly displays excellent antimicrobial properties. In this study, MEO was loaded into chitosan nanoparticles (CSNPs). The characteristics, antibacterial properties and benefit in pork preservation of MEO-CSNPs were evaluated. The MEO-CSNPs displayed an excellent encapsulation efficiency (EE) (67.32%–82.35%), the particle size values of 131.3 nm–161.9 nm, and the absolute zeta potential values above 30 mV. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, and thermogravimetric analysis (TGA) revealed that the MEO was incorporated into CSNPs without requiring a chemical reaction, the antibacterial activity of the MEO remained. Furthermore, the damage of MEO-chitosan nanoemulsions (MEO-CSs) to the cell membranes of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was confirmed by the change of bacterial cell morphology. The anti-biofilm assays verified that the MEO-CSs substantially inhibited biofilm formation and destroyed the mature biofilms. MEO-CSs were also applied to pork, proving a great potential for pork preservation. This study provides a potential approach for developing and utilizing MEO-CSs as natural antimicrobial agents in the food industry.