Preparation of active antimicrobial and antifungal alginate-montmorillonite/lemon essential oil nanocomposite films

The inclusion of antimicrobial and antifungal agents such as essential oils directly into a food packaging material is a form of active packaging elaboration. In this work, alginate-based films activated with lemon essential oil (LEO) at increasing concentration levels [0.5%, 1% and 1.5% (v/v)] were prepared, and their antibacterial and antifungal activities were investigated. The microstructure characterisation of alginate-montmorillonite/LEO (alg-MMT/LEO) nanocomposites was performed using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) and the surface morphology of the films was examined using light microscopy. The XRD and FTIR results confirmed MMT exfoliation and revealed the presence of strong interaction between alginate and MMT in the presence of LEO. Thermogravimetric analysis (TGA) indicated that LEO-containing films exhibited a higher degradation temperature in comparison with pure alginate films. Powerful antimicrobial and antifungal properties of the films were also highlighted at 1.5% LEO concentration, suggesting that the formulated nanocomposites might be considered as promising active packaging materials.