Polyethylene glycol enhanced encapsulation of thymol in metal-organic framework nanocarriers for antimicrobial food packaging.

Thymol is a natural and environmentally friendly antibacterial agent. A novel Zirconium-based metal-organic framework (UiO-66) coated with polyethylene glycol (PEG) serves as thymol carrier. This carrier was incorporated into chitosan/polyvinyl alcohol (CS/PVA) films for antimicrobial applications. Characterization showed that PEG was coated on the surface of UiO-66 without disrupting the structure of UiO-66. The coating of PEG prevented the evaporation of thymol before 270 °C and decreased the release rate of thymol with retention of 12.3 %. UiO-66 retained its octahedral structure when combined with CS/PVA films, which was beneficial to the continuous release of thymol. Antimicrobial activity experiments demonstrated that CS/PVA with UiO-66 loaded with thymol had excellent inhibition of E. coli, along with an inhibition zone of 16 mm. Overall, the antimicrobial films developed in this study hold promising potential for applications in the food industry.