Characterization of nanocomposite films based on chitosan and carboxymethylcellulose containing Ziziphora clinopodioides essential oil and methanolic Ficus carica extract

Abstract

The aim of the present study was to improve different characteristics including antibacterial, antioxidant, and some physicomechanical properties of chitosan-nanomontmorillonite (Ch-MMT) and carboxymethylcellulose-nanomontmorillonite (CMC-MMT) films by incorporating Ziziphora clinopodioides essential oil (ZEO; 1 and 2%) separately and in combination with methanolic Ficus carica extract (FCH; 1%). The major compounds of the ZEO identified by gas chromatography–mass spectrometry were carvacrol (65.22%) and thymol (19.51%). Incorporation of natural compounds into Ch-MMT and CMC-MMT films could improve antibacterial and antioxidant activities, thickness as well as water vapor and oxygen barrier properties. Moreover, ZEO separately and in combination with FCH decreased water sorption property, tensile strength, elongation at break, puncture force, and puncture deformation of Ch-MMT and CMC-MMT films. The highest antibacterial (inhibition zone: 13.6–27.4 mm) and antioxidant (2,2-diphenyl-1-picrylhydrazyl hydrate scavenging activity: 39.96%) effects was found for Ch-MMT film containing ZEO 2% + FCH 1%. The lower lightness (L*: 17.96 ± 0.03), higher redness (a*: 24.53 ± 0.32), higher yellowness (b*: 8.13 ± 0.09), and subsequently a darker and reddish color was found in Ch-MMT film containing ZEO 2% + FCH 1%. This study indicated some benefits of addition of ZEO and FCH into Ch-MMT and CMC-MMT films and their potentials for application as biodegradable active packaging. Practical applications Production of biodegradable polymers from natural renewable resources is one of the major points of interest in the food industry area due to concern regarding the use of plastic packaging materials and also increasing consumer interest for improvement of quality and appearance of food products. According to the results of the present study, chitosan-nanomontmorillonite and carboxymethylcellulose-nanomontmorillonite films containing Ziziphora clinopodioides essential oil and Ficus carica extract can be used as food packaging materials in food industries.