The potential of chitosan-based film with curry leaf essential oil as natural insect-repellent food packaging

This research investigated the effect of curry leaf essential oil (CLEO) on the properties of chitosan-based film and its potential as a natural insect-repellent film. CLEO was added at different concentrations (0.5–1.5 %) with Tween 80 (0.1–0.3 %) as a surfactant. Chitosan-CLEO matrix films successfully reduced (p < 0.05) the moisture content, film water solubility and water vapor permeability values. The incorporation of Tween 80 at 0.3 % (of distilled water) further improved (p < 0.05) the film's moisture and water barrier. Films containing more CLEO showed higher total phenolic compound and antioxidant activity with the DPPH (2, 2-diphenyl-1-picrylhydrazyl) % increased significantly (p < 0.05) from 19.07 % to 33.67 %. The chitosan-CLEO film-forming emulsion (FFE) also inhibited the Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative bacteria (Escherichia coli and Salmonella typhimurium), indicating the potential of CLEO as antibacterial agents. Meanwhile, chitosan film incorporated with 0.5 % CLEO successfully repelled at least 60–70 % of Musca domestica in the area preference test, while the films enriched with 1.0 % CLEO and 0.3 % Tween 80 showed 100 % repellency. Repellency results are considered very promising for chitosan-CLEO films to develop as active packaging with a natural repellent effect

Physicochemical characterization of kappa-carrageenan (Euchema cottoni) based films incorporated with various plant oils

This study investigated the effects of different types of plant oil (olive oil, corn oil, soybean oil and sunflower oil) on the physical and mechanical properties of kappa-carrageenan films from Euchema cottoni species. The incorporation of plant oils increased the film thickness significantly (P < 0.05). However, the moisture content, solubility and tensile strength of films decreased significantly (P < 0.05) as plant oils were added. The incorporation of plant oils also contributed to a plasticizing effect, whereby the values for elongation at break increased significantly (P < 0.05), from 22.3% to 108.8%. Higher oil content also led to carrageenan films with lower opacity, which contradicted with previous studies. In conclusion, the plant oils used in this research significantly improved film properties, thus demonstrating the potential of these materials to be used as food packaging films and coatings