Morphological, physico-mechanical, and antimicrobial properties of sodium alginate-montmorillonite nanocomposite films incorporated with marjoram essential oil

Combined effect of montmorillonite nanoclay (MMT) (3%w/w) and Origanum majorana essential oil (MO) (0.5, 1.0, and 1.5%v/v) on microstructural (SEM, TEM, and XRD), water sensitivity, barrier, mechanical, thermal, and antibacterial properties of sodium alginate (SA) was studied. Results showed that, addition of both MMT and MO reduced water solubility of SA film up to 47% while MO increased water vapor permeability of SA/MMT films. MO improved surface hydrophobicity of SA/MMT film but tensile strength tend to decrease when both MMT and MO ( 1%v/v) were added into film formulation. The nanocomposite film inhibited the growth of Escherichia coli, Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus at 1.5% MO concentration confirming the functionality of the films. Finally, combined application of MMT and MO could provide a tool for developing an active SA film with minimized side effects caused by the hydrophobic nature of the essential oil. Practical applicationHuge amounts of synthetic packaging materials used during last decades has caused serious environmental problems resulting great efforts by both governments and researchers for finding innovative alternatives for the conventional packaging materials. Biodegradable packaging materials has been introduced as a promising solution for the problem. Biodegradable packaging materials like biopolymer based films can be produced from proteins, carbohydrate and lipids and can be replaced or complement traditional packaging systems. Up to now, biopolymer-based packaging materials have been partially successfully used to prolong the shelf life of food products. However, there are still new developments in various fields and from various perspectives worth reporting. This study developed and characterized a biodegradable and antimicrobial nanocomposite films by incorporating MMT nanoparticles and marjoram essential oil in sodium alginate matrix.