Chitosan nanoencapsulation of patchouli essential oil/V-doped ZnO nanoparticles for enhanced antimicrobial performance on plasma-treated polybutylene adipate terephthalate films

In this study, various chitosan (Cst) nanocapsules loaded with patchouli essential oil (PEO) and vanadium zinc oxide (V-ZnO) nanoparticles were prepared using a nanoemulsion approach and employed as an active coating on polybutylene adipate terephthalate (PBAT) films. Transmission electron microscopy (TEM) confirmed the synthesis of loaded chitosan nanocapsules, showing sizes of 100–250 nm with zeta potentials ranging 28–38 mV. Thermal analysis revealed enhanced PEO thermal stability due to the encapsulation. The NC_6 formulation (80 %Cst,10 %PEO,10 %V-ZnO) exhibited a distinct controlled release of PEO, achieving 76.03 % higher retention than other formulations. Moreover, NC_6 showed outstanding inhibition of selective gram negative and positive foodborne pathogens with NC_6 reducing Escherichia (E.) coli and Staphylococcus (S.) aureus bacterial growth by 97.09 % and 96.78 %, respectively, compared to the control samples. Disc diffusion analysis showed greater inhibition zones for NC_5 (E. coli: 19.17 ± 1.19 mm, S. aureus: 18.83 ± 1.10 mm) and NC_6 (E. coli: 20.83 ± 1.14 mm, S. aureus: 20.67 ± 1.15 mm) compared to samples without nanocapsules. PBAT film subjected to 4-min Ar/O₂ plasma treatment exhibited improved hydrophilicity, reducing the water contact angle (WCA) from 80.65 ± 1.27˚ to 17.66 ± 1.64˚ (78.10 % reduction). Therefore, the nanocapsule coated films demonstrated promising capacity for packaging applications.