Kinetics and mechanisms of Zn 2+ release from antimicrobial food packaging based on poly (butylene adipate-co-terephthalate) and zinc oxide nanoparticles

Intended for use in the food packaging field, active PBAT/ZnO bionanocomposite films were successfully prepared by solvent casting and characterized by several techniques. The antibacterial performance of these nanomaterials was evaluated against three bacterial strains (Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis), and a Zn2+ ions liberation study was also carried out, focusing thus their potential and effectiveness in food packaging industry application. The viability curves of PBAT/ZnO samples against the three bacterial strains showed a considerable decrease in bacteria’s number, confirming therefore the high antibacterial performance of these nanocomposite films, against both of Gram-positive and Gram-negative bacteria, whereas the Zn2+ release profiles have approved a long-term controlled release during a time period exceeding 45 days. Furthermore, the kinetic modeling of Zn2+ ions release plots indicates a good fit with Higuchi and Korsmeyer–Peppas models, and describing therefore the combination of three physicochemical phenomena: dissolution, diffusion and degradation, as mechanism inducing thus the controlled Zn2+ ions release.