Development of insect-proof starch adhesive containing encapsulated cinnamon oil for paper box adhesion to inhibit Plodia interpunctella larvae infestation.

Abstract

The objectives of this study were to develop insect-resistant adhesives and apply them to a cardboard packaging system for preventing Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) larvae infestation. Cinnamon essential oil (CO), an insecticide, was encapsulated with maltodextrin (CS/MD/CO), β-cyclodextrin (CS/β-CD/CO), and polyvinyl alcohol (CS/PVA/CO) in corn starch (CS) paste. This resulted in a sustained and gradual release of CO from the starch-based insect-proof adhesives. Penetration pathways of insects into corrugated cardboard boxes were investigated through the use of a screening test for infestation profiling. Microscopic images of encapsulated CO in an oil in water (O/W) emulsion were observed to confirm the morphology of the adhesives. Adhesion forces of CS, CS/CO, CS/MD/CO, CS/β-CD/CO, and CS/PVA/CO were determined to be 6.2 N, 4.0 N, 3.1 N, 6.0 N, and 5.8 N, respectively. Consequently, significant decreases of adhesion force in the CS/CO and CS/MD/CO were found to be due to the presence of the surfactant (Span® 80) and the low adhesive properties of MD. The duration of the insecticidal activities of the developed adhesives was evaluated by measuring their release rates for 14 days and repellent profiles up to 24 hr and 40 days. As a result, CS/β-CD/CO and CS/PVA/CO were found to have an inhibited rapid release and sustained repellent profiles. In conclusion, CS/β-CD/CO and CS/PVA/CO were determined to be suitable for encapsulation models and could be applied to industrial cardboard containers to prevent cases of insect invasion. PRACTICAL APPLICATION: Corn starch-based natural adhesives with an insect-proof property were applied to food containers consisted of corrugated cardboard boxes. Cornflake cereal packaging using insect-proof corrugated cardboard successfully prohibited pest invasion in commercial food distribution simulation model. Developed insecticidal adhesives are able to control insect penetration in distribution and storage steps.