Konjac glucomannan-based edible films loaded with thyme essential oil: Physical properties and antioxidant-antibacterial activities

The objectives of this study were to develop the edible films based on konjac glucomannan (KGM) loading with different concentrations of thyme essential oil (TEO) (0-1.6 %, v/v) and investigate their properties. The microstructure analyses showed that TEO was evenly distributed in the films and significantly influenced the roughness of the films. Moreover, the hydrophilic characteristics of KGM films were significantly decreased with the increase of TEO concentrations. The tensile strength of the TEO-loaded KGM films decreased, while the elongation at break increased as the concentrations of TEO increased. Furthermore, KGM films exhibited an increase of antioxidant capacities with the increased TEO concentrations. Additionally, the TEO-loaded KGM films also presented some certain antibacterial activities against L. monocytogenes, S. aureus and E. coli O157:H7. Taken together, this study suggested that the development of TEO-loaded KGM films was a promising way to improve the physical properties, antioxidant and antibacterial activities of the pure KGM film.