Effect of plasticizer type and essential oils on mechanical, physicochemical, and antimicrobial characteristics of gelatin, starch, and pectin-based films

Plastic packaging has been widely criticized due to the environmental pollution it entails. Biopolymer-based films could provide an interesting eco-friendly alternative. This study aimed to investigate the effect of plasticizer type on the physicochemical and mechanical properties of gelatin, pectin, starch, gelatin/pectin, gelatin/starch, and starch/pectin-based films. Films were prepared using the casting method. Among the six types of films studied, gelatin/pectin-based film plasticized with sorbitol displayed the best functional properties. Tensile strength and elongation at break were 52.46 MPa and 19.80%; moisture content, water vapor permeability, and water resistance were 19.96%, 3.24 x 10(7) g s(-1) m(-1) Pa-1, and 19.96%, respectively. Mentha pulegium and Lavandula angustifolia essential oils were incorporated into the selected film and their effects on the film's characteristics were evaluated. The incorporation of essential oils resulted in films with enhanced antibacterial properties, lower water vapor permeability, and reduced mechanical properties. Practical applications Biopolymer-based films have attracted widespread attention as an alternative to plastic packaging. In this study, we have demonstrated that gelatin/pectin-based film plasticized with sorbitol at 30% displayed good mechanical and physicochemical properties. The incorporation of Mentha pulegium and Lavandula angustifolia essential oils into this matrix resulted in films with important antimicrobial activity and adequate mechanical and physicochemical characteristics. The selected combination could be used as bioactive packaging to preserve and prolong the shelf life of food.