Absorption of Ajwain Essential Oil on Chitosan to Enhance Antibacterial Activity of Polyethylene-based Composite Food Packaging Films

Abstract

In this research, we prepared an antibacterial packaging composite film for food packaging. Ajwan essential oil (AEO) was adsorbed onto chitosan (CS) particles, which were loaded in a combination of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and polyethylene graft-maleic anhydride (PEma, 4%). Gas chromatography (GC) results confirmed successful AEO adsorption on chitosan particles, with protection from evaporation during the film formation process. Additionally, inhibition zone (IZ) tests demonstrated increased antibacterial activity in the film. Mechanical tests revealed that AEO incorporation decreased tensile strength but increased elongation at break, while CS reduced elongation at break. CS particles in PE-7.5-0 (910 cm³/m²·day·bar) reduced oxygen permeability compared to PE-0-0 (1680 cm³/m²·day·bar), but adding AEO increased oxygen permeability (PE-0-10, 2200 cm³/m²·day·bar). The antibacterial activity results indicated a synergistic inhibitory effect of CS and AEO. The composite film containing 7.5% chitosan and 10% adsorbed AEO (PE-7.5-10) exhibited suitable mechanical properties and improved antibacterial behavior due to AEO adsorption on CS. Consequently, it can be considered a suitable candidate for food packaging.