The aim of this study was to examine the effect of Sage (Salvia sclarea) essential oil (SEO) on the physiochemical and antioxidant properties of sodium alginate (SA) and casein (CA) based films. Thermal, mechanical, optical, structural, chemical, crystalline, and barrier properties were examined using TGA, texture analyzer, colorimeter, SEM, FTIR, and XRD. Chemical compounds of the SEO were identified via GC-MS, the most important of which were linalyl acetate (43.32%) and linalool (28.51%). The results showed that incorporating SEO caused a significant decrease in tensile strength (1.022-0.140 Mpa), elongation at break (28.2-14.6%), moisture content (25.04-14.7%) and transparency (86.1-56.2%); however, WVP (0.427-0.667 × 10-12 g·cm/cm2·s·Pa) increased. SEM analysis showed that the incorporation of SEO increased the homogeneousness of films. TGA analysis showed that SEO-loaded films showed better thermal stability than others. FTIR analysis revealed the compatibility between the components of the films. Furthermore, increasing the concentration of SEO increased the antioxidant activity of the films. Thus, the present film shows a potential application in the food packaging industry.
Keywords: antioxidant activity; casein; edible films; food packaging; sage essential oil; sodium alginate.