Evaluation of physicomechanical, antimicrobial and microstructural properties of chitosan bioactive films containing Eucalyptus globulus essential oil

Antimicrobial packaging is a type of active packaging that provides the continuous migration of antimicrobial agents to the surface of food products. In this study, chitosan bioactive films containing Eucalyptus globulus essential oil (EGOs) (at concentrations of 0.5, 1 and 1.5 % v/v) were produced by casting method and their antibacterial, physical, mechanical and microstructural properties were examined. The results of disc diffusion test revealed that chitosan film containing 1 and 1.5 % essential oil was able to reduce the density of bacteria. The addition of EGO into chitosan based films reduced the moisture content, solubility in water, water vapor permeability and tensile strength of bioactive films to 41.28 %, 39.08 %, 25.36 % and 27.3 % respectively, while increased elongation at break (65.61 %) as well as its thickness. It seems that physical and mechanical properties of chitosan films containing EGO is related to the formation of bonds between the essential oil compounds and functional groups of chitosan, which consequently improved the physical properties but decreased the mechanical properties. Also, the electron microscopy images confirmed the results obtained in this study. The results of this study indicated that these natural compounds have a great potential to be applied in active packaging materials due to their effective antimicrobial and physical properties.