The aim of the present study was to prepare whey protein isolate (WPI)-based films containing Citrus sinensis peel essential oil (CSEO) loaded emulsions and nanoemulsions (2.5% and 5% of WPI), as an active packaging system. The fabricated films were characterized by Fourier transform infrared spectroscopy, Filed Emission Scanning Electron Microscopy, X-ray diffraction, and tensile analyses. The obtained results approved the appropriate interactions between WPI matrix and CSEO emulsion and nanoemulsion due to their good compatibility. The incorporation of nanoemulsion significantly improved the water barrier properties of the film samples. Additionally, the antioxidant and antimicrobial activities of the CSEO nanoemulsion incorporated films were significantly higher than those of the emulsion incorporated films. As a result, the developed active WPI-based film containing CSEO nanoemulsion can be suggested as a suitable food packaging system for the preservation of foodstuffs against oxidation and microbial spoilage. Practical applications Biodegradable active packaging is an alternative new technology for preserving the quality and safety of food products, often achieved by the incorporation of antibacterial and antioxidant ingredients into the biopolymer-based packaging system. The application of whey protein isolate-based active films containing orange peel essential oil nanoemulsions, as an active packaging system, would be a positive step in improving shelf life and quality of foodstuffs.
