Identification of the major active compounds in cinnamon bark with Plodia interpunctella repellent properties and insect-proof activity of poly(vinyl alcohol), xanthan gum, and trans-cinnamaldehyde-based strips and sachets

Plodia interpunctella is the primary insect that penetrates food packaging during storage, causes significant economic losses, and poses great health risks to consumers. In this study, we identified the repellent compounds and component with the strongest insect-repellent activity in cinnamon bark extract using solvent–solvent partitioning, column chromatography, thin-layer chromatography, and gas chromatography–mass spectrometry. Trans-cinnamaldehyde (TC), which was the strongest insect-repellent compound, was used to fabricate insect-proof packaging. Poly(vinyl alcohol) (PVA) and xanthan gum (XG) blended with different weight mixing ratios [100:0, 90:10 (PVA90/XG10), 80:20, and 70:30] were used to fabricate strips, and the TC content and TC loading efficiency of the fabricated strips were evaluated. Thereafter, insect-proof sachets with or without the optimal TC-containing strips, which comprised PVA90/XG10, were fabricated, and their characteristics, such as the TC release profile and pest-repellent and insecticidal properties were evaluated. According to the repellent and infestation assays, TC-containing sachets can protect food from P. interpunctella infestation.