Development of carboxymethyl cellulose–chitosan based antibacterial films incorporating a Persicaria minor Huds. essential oil nanoemulsion

Abstract

As plastic waste has continued to increase over the years, there is an appeal for environmental-friendly packaging containing bioactive components such as essential oil for food packaging. However, the loss of activity and insolubility of essential oil in biopolymer-based packaging film remains a challenge. Hence, this study aimed to develop a carboxymethyl cellulose (CMC)–chitosan (CS) based antibacterial film containing a Persicaria minor Huds. essential oil nanoemulsion. The coarse-emulsified and nanoemulsified P. minor Huds. essential oils were evaluated to select the desirable emulsion type for the polymer-based film. Different concentrations of the selected essential oil emulsion (0, 4%, 8%, and 12% v/v) were incorporated into the 1.5 : 1% (w/v) CMC–CS based film. The nanoemulsion exhibited a smaller droplet size, lower whiteness index, and higher antibacterial activity as compared to the coarse emulsion. The addition of the P. minor Huds. essential oil nanoemulsion in the composite film lowered Young's modulus, resulting in a more flexible and less rigid film. The 12% (v/v) essential oil nanoemulsion film displayed desirable characteristics with 0.15 mm thickness, 11.52 A₆₀₀/mm opacity, 65.5% water solubility, and the lowest moisture content (19.21%) among the different concentrations. Additionally, the 12% (v/v) nanoemulsion CMC-CS based film had the least irregular surface structure, highest antioxidant activity (4.25 mg TE g⁻¹), and antibacterial activity against Escherichia coli and Bacillus subtilis (7.19 and 7.85 mm) as compared to other concentrations. The present work demonstrates the potential of the P. minor Huds. essential oil nanoemulsion in CMC–CS based film as bioactive packaging to prevent the presence of common foodborne pathogens in food products.