Chitosan/acetylated starch composite films incorporated with essential oils: Physiochemical and antimicrobial properties

Due to increasing environmental concerns regarding plastic waste, the development of edible and biodegradable films from natural polymers and food additives is gaining more attention. In this study, chitosan/acetylated starch composite films containing cinnamon and clove essential oils were fabricated via a solution-casting technique. The effects of essential oil concentration on the physical, mechanical, barrier, microstructural, and antimicrobial properties of the films were evaluated. Films incorporated with the essential oils were darker, redder and yellower than control films without essential oils. The moisture content and water solubility of the films decreased by 22.7% and 21.6%, respectively, with the incorporation of 2.50% of essential oils. The incorporation of 2.00% of essential oils decreased the tensile strength and elongation at break of the films by 25.6% and 40.4%, respectively. All the films incorporated with essential oils displayed enhanced light, water vapor, and oxygen barrier characteristics. As the essential oil concentration increased to 2.50%, the film opacity increased by 795.8%, while the water vapor permeability and peroxide value decreased by 35.5% and 52.6%, respectively. Fourier Transform Infrared spectroscopy and scanning electron microscopy results demonstrated well-dispersed essential oils in the polymer matrix. The films incorporated with essential oils exhibited excellent antibacterial activity against spoilage bacteria and the pathogen, Escherichia coli O157:H7, on beef. In conclusion, the films incorporated with essential oils displayed excellent barrier and antimicrobial properties and have a good potential to be used for edible food packaging applications.