Physicochemical and Mechanical Properties of Sodium Alginate Films Containing Thyme Essential Oil

In this study, it was aimed to develop edible film by the casting technique from sodium alginate (SA) (%2 w/v) using three different concentrations of thyme essential oil (TEO) (0.5%, 1%, 1.5% v/v). The physicochemical, mechanical, structural, and antioxidant properties of enriched SA films were also characterized. The highest film solubility (FS) was found as 91.78% in SA (control) films. The mechanical properties of films were found between 27.14 MPa and 50.06 MPa for tensile strength (TS) and between 13.88% and 32.02% for elongation at break (EAB). The highest total phenolic content (TPC) and antioxidant activity were found as 382.19 mg GAE/kg and 16.20% in SA film incorporated with TEO 1.5% respectively. As the concentration of TEO increased, the L* value increased, leading the film colors to approach white. Additionally, it was observed that as the b* value increased the film colors tented towards yellow. When the results of SEM analysis were evaluated, it was found that SA films were more homogeneous than other films. In general, it was concluded that TEO at a concentration of %1 (v/v) improves the physical and chemical properties of sodium alginate film compared to other groups.