A bright future lies ahead for the application of natural biocomposites in the food industry. In this research, edible biocomposite films were created using sodium caseinate (SC)-gum tragacanth (GT) and incorporating carum carvi seed essential oil (EO) as a nanoemulsion. Different ratios of oil were used as variables. The physical properties, structural morphology, mechanical characteristics, and thermal behavior of the films were evaluated. Furthermore, the preservative effects of these edible films were studied to prolong the shelf life of black mulberries over a period of 10 days at 4 °C. The findings indicated that the increase of EO content to the edible films resulted in a significant increase in thickness, tensile strength, opacity and water vapor permeability. Conversely, the elongation at break, water solubility and moisture content decreased with the rise in oil content up to 3.9%. Also the visual appearance and sensory evaluation of the fruits revealed that black mulberries covered with edible films containing 2.6 and 3.9% oil were more preferred compared to the other groups. The integration of caraway oil into the SC-GT biocomposite has been investigated for the first time, demonstrating that the resulting films are effective in prolonging the shelf life of black mulberries.