A Comparative Study on the Structural, Physicochemical, Release, and Antioxidant Properties of Sodium Casein and Gelatin Films Containing Sea Buckthorn Oil

The aim of this study was to compare the effect of increasing concentrations (0, 1, 2, 4%) of sea buckthorn oil (SBO) on the structural, physicochemical, release, and antioxidant properties of glycerol-plasticized sodi-um casein (NaCAS) and gelatin (GEL) films. Ultrasonic treatment ensured effective homogenization of SBO in both types of emulsions, resulting in yellow-tinted semi-opaque films with relatively low mi-cro-roughness. Generally, GEL films exhibited lower UV barrier properties and solubility, but better trans-parency, surface hydrophobicity, oxygen barrier performance, strength, and antiradical activity compared to NaCAS-based counterparts. Despite reducing the surface hydrophobicity of GEL films, the presence of SBO significantly limited their solubility and water absorption. SBO, in a concentration-independent man-ner, improved the water vapor barrier properties of both films and increased the oxygen permeability of the GEL film. At the highest SBO concentration, the tensile strength of NaCAS- and GEL-based films de-creased by 27% and 20%, respectively, while their antiradical activity increased by 9.3x and 4.3x (based on time required for the half-neutralization of 2,2-diphenyl-1-picrylhydrazyl radicals). Migration studies showed that at the lowest concentration, SBO was released (into 95% ethanol) approximately 2x faster from the GEL-based film than from the NaCAS film, whereas at higher concentrations, the trend reversed.