Antibacterial hydroxypropyl methyl cellulose edible films containing nanoemulsions of Thymus daenensis essential oil for food packaging

Edible films containing essential oils (EO) as natural antibacterial agents are promising systems for food preservation. In this work, nanoemulsions of Thymus daenensis EO (wild; F1 and cultivated; F2) were loaded in hydroxyl propyl methyl cellulose (HPMC) films and the effect of different parameters (polymer, plasticizer, and EO concentration) on the film properties were analyzed and optimized. Prepared HPMC films were characterized in terms of EO loading, morphology, mechanical properties, and the antibacterial activity. The results of SEM showed uniform incorporation of nanoemulsions into the edible film. Investigation of the mechanical properties of two edible films revealed a plasticizing effect of T. daenensis EO on the films. Also, edible films had noticeable antimicrobial activity against selected microorganisms, i.e. 47.0 +/- 2.5 mm and 22.6 +/- 0.5 mm zone of inhibition against S. aureus for films containing F1 and F2, respectively. Incorporation of nanoemulsions into the HPMC films can be used for active food preservation. (C) 2017 Elsevier Ltd. All rights reserved.