RESUMO
A multifunctional film with insect-repellent and antimicrobial activities was developed. Star anise (Illicium verum Hook. f.) oil (SO) proved to be effective in repelling Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) larvae and was selected as an insect-repellent agent. Thymol, a compound that demonstrated strong growth inhibition activities against both Staphylococcus aureus and Penicillium roqueforti, was selected as an antimicrobial agent. Based on the release profile test of SO using various plastic films, polypropylene (30 µm; PP 30) and low-density polyethylene (20 µm; LDPE 20) were selected as laminated films for sustainable insect-repellent and strong antimicrobial effects, respectively. Further, polyethylene terephthalate (12 µm; PET 12) was selected as an intermediate barrier layer. Finally, structure of the multilayer film was designed as PP 30/SO/PET 12/thymol/LDPE 20. The developed film demonstrated insect-repellent activity for >3 weeks, antibacterial activity for >2 weeks, and antifungal activity for 1 week. The results indicated that the developed multilayer film structure possessed strong, sustained insect-repellent and antimicrobial effects, providing a new possibility for the industrial applications to food packaging. PRACTICAL APPLICATION: A multifunctional active packaging film with insect-repellent and antimicrobial activities was developed. Star anise oil and thymol that showed insect-repellent and antimicrobial activities (antibacterial and antifungal activities), respectively, were added in coating layers in the multilayer film structure. The developed multilayer film proved an efficient insect-repellent activity against Plodia interpunctella for >3 weeks. Also, strong antibacterial and antifungal activities of the developed multilayer film were proved against Staphylococcus aureus and Penicillium roqueforti, respectively. The developed film has a potential for the industrial use to the food packaging material.