Production of edible film based on gelatin containing thyme essential oil: investigation of its physicochemical, mechanical, antioxidant and microbial properties

Considering the tendency to use biodegradable packaging films and increase their antimicrobial ability in recent years, this study aims to investigate different concentrations of thyme essential oil to improve edible film with physicochemical, mechanical, antioxidant and Antimicrobial was done. The effect of different concentrations of thyme essential oil for the production of edible films on the physicochemical, mechanical, antioxidant and antimicrobial properties was investigated with a completely randomized design in three replications and Duncan's multi-range test using Minitab18  software at a probability level of 0.05 were investigated. The highest tensile strength and elongation at break point was 2.5% in the treatment. In the treatment of films, the lowest solubility was observed at a concentration of 3.75% and permeability at a concentration of 2.5% of essential oil. In all treatments, the turbidity was significant, and in the concentration of 3.75% essential oil, the turbidity was the highest, and in the same concentration, the highest thickness was 0.13 mm, which was not significant in all treatments (p<0.05). p). In all edible film treatments, the antioxidant property using DPPH radicals was significant (p<0.05). The results of evaluating the antimicrobial activity of the film use of diffusion disks method showed that the largest diameter of the inhibition halo in the concentration of 3.75% was related to Staphylococcus aureus with an average halo diameter of 15.33 mm. Average halo diameter was reported for Pseudomonas aeruginosa and Escherichia coli, 8.6 mm and 9.52 mm, respectively. The general results showed that the addition of thyme essential oil at a concentration of 2.5% produced films that, in addition to inhibiting the growth and proliferation of bacteria, have sufficient strength and are also capable of being used in perishable food.