Insect-resistant films containing a microencapsulated insect-repelling agent were developed to protect food products from the Indian meal moth (Plodia interpunctella). Cinnamon oil (CO), an insect repelling agent, was encapsulated with gum arabic, whey protein isolate (WPI)/maltodextrin (MD), or poly(vinyl alcohol) (PVA). A low-density polyethylene (LDPE) film was coated with an ink or a polypropylene (PP) solution that incorporated the microcapsules. The encapsulation efficiency values obtained with gum arabic, WPI/MD, and PVA were 90.4%, 94.6%, and 80.7%, respectively. The films containing a microcapsule emulsion of PVA and CO or incorporating a microcapsule powder of WPI/MD and CO were the most effective (P < 0.05) at repelling moth larvae. The release rate of cinnamaldehyde, an active repellent of cinnamaldehyde, in the PP was 23 times lower when cinnamaldehyde was microencapsulated. Coating with the microcapsules did not alter the tensile properties of the films. The invasion of larvae into cookies was prevented by the insect-repellent films, demonstrating potential for the films in insect-resistant packaging for food products.
Practical application: The insect-repelling effect of cinnamon oil incorporated into LDPE films was more effective with microencapsulation. The system developed in this research with LDPE film may also be extended to other food-packaging films where the same coating platform can be used. This platform is interchangeable and easy to use for the delivery of insect-repelling agents. The films can protect a wide variety of food products from invasion by the Indian meal moth.
© 2013 Institute of Food Technologists®