Carboxymethyl cellulose-agar biocomposite film activated with summer savory essential oil as an antimicrobial agent

Carboxymethyl cellulose (CMC)-agar biocomposite film was developed by a solvent casting method and the effects of summer savory essential oil (SSEO) at 0.5, 1.0 and 1.5% v/v on antimicrobial, microstructural, mechanical and optical properties as well as water sensitivity of the films were studied. Results showed that incorporation of SSEO into the biocomposite film developed active films with good growth inhibition activity against Gram-positive bacteria (S. aureus, B. cereus and L. monocytogenes) and less powerfully against Gram-negative bacteria (E. coli). Addition of the SSEO at 1.0 and 1.5% increased microstructural heterogeneity of the films and hence significantly (p < 0.05) increased water vapor permeability of the films while reducing their tensile strength. In contrast, mechanical flexibility and surface hydrophobicity of the films were significantly (p < 0.05) improved as a function of SSEO addition. The active films showed substantially lower swelling ratio compared to the CMC-agar film when 1.5% SSEO was added, but the transparency of the films was reduced. Finally, the results showed that SSEO can act as an antimicrobial agent in combination with CMC-agar film. However, it modifies properties of the film depending on the applied concentration. (C) 2018 Elsevier B.V. All rights reserved.