Characterization of antioxidant-antibacterial quince seed mucilage films containing thyme essential oil

In this study thyme essential oil (TEO) concentrations ranging from 0% to 2.0%, incorporated in quince seed mucilage (QSM) film were used. Antibacterial activity, physical, mechanical, barrier and antioxidant properties of QSM films were evaluated. The antimicrobial activity of the QSM films incorporated with thyme essential oil was screened against 11 important food-related bacterial strains by agar disc-diffusion assay. Films containing 1% of thyme essential oil were effective against all test microorganisms and exhibited a strong inhibitory effect on the growth of Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus. QSM films exhibited some antioxidant activity, which was significantly improved by the addition of the essential oil. A reduction of the glass transition temperature, as determined by differential scanning calorimetry (DSC), was caused by addition of thyme essential oil into the QSM films. Scanning electron microscopy was carried out to explain structure-property relationships. Incorporating thyme essential oil into edible QSM films provides a novel way to improve the safety and shelf life of ready-to-eat foods.