Cinnamon and ginger essential oils to improve antifungal, physical and mechanical properties of chitosan-carboxymethyl cellulose films

The aim of this study was to investigate the effect of cinnamon and ginger oils on some biological, physical and physico-chemical properties of chitosan-carboxymethyl cellulose films emulsified with oleic acid. Films containing cinnamon oil showed higher antifungal activity in vitro against Aspergillus niger than those containing ginger. Unlike ginger-based materials, the film crystallinity decreased with an increasing concentration of cinnamon oil. The microstructure of the active films was evaluated by scanning electron microscopy and results showed a distinct morphology depending on the composition of essential oils (EOs). As expected, both EOs decreased water vapor permeability of the active films, with a higher decreasing effect for cinnamon. Resulting water contact angles were improved by 36-59% for ginger films and 65-93% for cinnamon films, depending on the EO concentration. Regarding mechanical properties, highest concentrations of EOs led to an improvement of 328% and 111% of the elongation with cinnamon and ginger, respectively. The different behavior of both EOs regarding physical, mechanical, thermal and water vapor permeability properties could be attributed to differences in their chemical compositions. The presence of cinnamaldehyde, in cinnamon essential oil, can create many kinds of interactions with the network made by carboxymethyl cellulose, chitosan and oleic acid. Findings in this work suggest that EOs and especially cinnamon oil could be used to plasticize chitosan-carboxymethyl cellulose films while improving moisture permeability and maintaining antifungal activity. This biobased material could be of interest for food preservation. (C) 2017 Elsevier Ltd. All rights reserved.