Combined effects of two kinds of essential oils on physical, mechanical and structural properties of chitosan films

The combined effects of plant essential oils (lemon, thyme, cinnamon) on the physical and structural properties of chitosan-based films were investigated. Results showed that the apparent viscosity and average particle size of lemon essential oils were significantly lower than that of the thyme and cinnamon essential oils. The combined use of two kinds of essential oils decreased the particle size and water vapor permeability compared with the use of a single essential oil. However, the combined use of two kinds of essential oils balanced the antibacterial properties of the single essential oil. SEM analysis showed that the oil droplets were homogenously distributed across the film. The emulsification was obviously observed in chitosan/lemon/cinnamon essential oils composite films due to the electrostatic interaction of limonene and cinnamaldehyde. This study revealed that an active chitosan film could be obtained by the combined use of two kinds of essential oils in the matrix, which might provide a new formulation option for developing antimicrobial film. (C) 2013 Published by Elsevier Ltd.