Alginate biocomposite films incorporated with cinnamon essential oil nanoemulsions: Physical, mechanical, and antibacterial properties

Abstract

Alginate-based antibacterial biocomposite films were prepared by incorporating with cinnamon essential oil nanoemulsions (CEO-NE). CEO-NE was first prepared by mixing and homogenizing the oil phase and aqueous phase containing polysorbate 80 (Tween 80), using a probe-type ultrasonication equipment. The biocomposite films were then prepared by incorporating the CEO-NE to an aqueous solution of alginate and glycerol, homogenizing, casting, and drying. The mean droplet size, zeta potential, and polydispersity index of the CEO-NE were 92.2 nm, −15.58 mV, and 0.25, respectively. Young’s modulus of the CEO-NE/alginate biocomposite films was significantly increased with an increasing concentration of CEO-NE, while their elongation at break was significantly decreased. However, the tensile strength of the CEO-NE/alginate biocomposite films was not significantly changed. The maximum tensile strength and elongation at break of the biocomposite films were 15.63 MPa and 23.67%, respectively, corresponding to the biocomposite films containing 20% CEO-NE. The biocomposite films containing 20% CEO-NE also showed strong antibacterial effects against Salmonella typhimurium, Bacillus cereus, Escherichia coli, and Staphylococcus aureus, achieving inhibition zones from 29.7 to 53.0 mm. These results show the potential of the CEO-NE/alginate biocomposite films as antibacterial packaging for extending the shelf life of fresh foods.