Effect of starch film containing thyme essential oil microcapsules on physicochemical activity of mango

Abstract

Essential oils are natural antibacterial substances with potential applications in packaging; however, due to their volatile and oxidizable properties, these materials have a low utilization rate. In this study, starch films containing thyme essential oil microcapsules (TEO-M) were prepared using the casting method, and the effect of the films on the quality and physicochemical properties of mango was evaluated. Scanning electron microscopy (SEM) image analysis showed that the structure of microcapsules presented higher integrity in starch films. The TEO-M starch film thermal stability was decreased compared to the stability of starch film alone. Fourier transform infrared (FT-IR) spectroscopy analysis revealed that TEO-M interacted effectively with starch films via hydrogen bonding. Furthermore, the TEO-M starch films showed an inhibitory effect against Botryodiplodia theobromae Pat and Colletotrichum gloeosporioides Penz. The addition of TEO-M to starch films increased the opacity, thickness, tensile strength and water solubility. Additionally, the TEO-M starch films presented lower elongation, moisture content and water vapor permeability. TEO-M starch films showed a better preservation effect compared with that of starch film alone. The shelf-life of mangoes treated with TEO-M starch films was 10 days at 25 °C. These results demonstrate the potential of developing TEO-M starch films for mango preservation.