Effects of Olibanum Essential Oil on Physicochemical, Structural, Antioxidant and Microbial Characteristics of Gelatin Edible Films

Background and Objectives: Active packaging is an improved form of conventional packaging that can preserve quality of foods and increase durability and safety of food products due to their antimicrobial and antioxidant characteristics.  Materials & Methods: In this study, effects of olibanum essential oil on physicochemical, structural, antimicrobial and antioxidant characteristics of gelatin edible films were investigated. Various concentrations of olibanum essential oil (0.2, 4 and 6% w/v) were added to the gelatin solutions. Results: Results showed that water vapor permeability and solubility decreased significantly in all treatments containing olibanum essential oil, compared to control treatments (with no olibanum essential oils) (p<0.05). Moreover, tensile strength and elongation at break increased significantly in all treatments compared to control treatments (p< 0.05). Fourier-transform infrared spectroscopy analysis showed good interactions between gelatin and olibanum essential oil components. Hydrogen and covalent electrostatic interactions between the gelatin network and olibanum essential oil compounds limited availability of the hydrogen groups to form hydrophilic bonds with water. Subsequently, tendency of the gelatin films to water decreased. In addition to antioxidant activity, treatments containing olibanum essential oil exhibited good antimicrobial activities against the Gram-positive and Gram-negative bacteria (Staphylococcus aureus, Escherichia coli and Bacillus cereus). Conclusion: Results of this study have shown that gelatin composite films containing olibanum essential oil can be used for food storage by decreasing chemical and microbial spoilages.