Physicochemical and functional enhancement of κ‐carrageenan films with olive oil for biodegradable active food packaging

Abstract This study investigates the incorporation of olive oil at concentrations of 1.5%, 3.0%, and 4.5% into κ‐carrageenan films to improve their physicochemical and antioxidant properties. Olive oil at 4.5% significantly ( p < 0.05) reduced water solubility by 26%, although it also elevated water vapor permeability and opacity. Similarly, 4.5% olive oil also resulted in significant ( p < 0.05) improvements in light barrier properties, particularly at wavelengths of 200, 280, and 400 nm. While tensile strength decreased with the incorporation of olive oil, elongation at break increased significantly ( p < 0.05), enhancing film flexibility. Thermal analysis indicated an elevation in melting temperature, peaking at 104.75°C for films with 4.5% olive oil. Confocal laser scanning microscopy (CLSM) revealed that a 1.5% oil concentration produced the most homogeneous structure. Antioxidant analysis showed increased ( p < 0.05) total phenolic content (22.02 mg GAE/100 g at 4.5% olive oil), with a corresponding rise ( p < 0.05) in DPPH radical scavenging activity and ferric reducing antioxidant power (FRAP). Overall, these enhancements suggest that olive oil not only improves the physical integrity but also adds functional antioxidant benefits to κ‐carrageenan films, highlighting their potential for active food packaging applications. Highlights Olive oil enhances κ‐carrageenan film flexibility and antioxidant properties. Increased olive oil reduces solubility but raises water vapor permeability. Higher olive oil concentrations increase film opacity and thermal stability. Confocal microscopy shows a homogeneous film at low olive oil concentration. κ‐carrageenan‐olive oil film is a promising active food packaging material.