Effect of cellulose and lignocellulose nanofibers on the properties of Origanum vulgare ssp. gracile essential oil-loaded chitosan films

In this study, active biodegradable films from chitosan (CS) containing 5% w/w Origanum vulgare ssp. gracile essential oil (EO) and 4% w/w cellulose nanofibers (CNF) or lignocellulose nanofibers (LCNF) as nanoreinforcement were developed. GC-MS analysis showed that the most components of EO were carvacrol (49.43%) and then γ-terpinene (17.71%). The CS-EO film had high antioxidant activity and was more effective against E. coli and B. cereus bacteria than bionanocomposite films, which shows the release controlling effect of CNF and LCNF on the bioactive compounds from CS films. EO had not significant effect on the mechanical properties of the films (p > 0.05), while nanofibers had significant effects (p < 0.05) on strain to break (STB) and ultimate tensile strength (UTS). Incorporation of EO and CNF/LCNF in the CS-film also considerably improved solubility and water vapor barrier properties of the films. Color properties were significantly affected by adding of EO and CNF/LCNF. Formation of new hydrogen bonds between the chitosan chains, the EO and nanofibers were confirmed using FT-IR spectroscopy. Morphology of films was viewed using AFM and SEM, suggesting good dispersion of the CNF/LCNF. In general, the properly dispersion state and improving effect of LCNF on properties of CH-EO films was more than CNF.

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