Cinnamon-Nanoparticle-Loaded Macroalgal Nanocomposite Film for Antibacterial Food Packaging Applications

Abstract

In addition to environmental concerns, the presence of microorganisms in plastic food packaging can be hazardous to human health. In this work, cinnamon nanoparticles incorporated with red seaweed (Kappaphycus alvarezii) biopolymer films were fabricated using a solvent casting method. Cinnamon was used as a filler to enhance the properties of the films at different concentrations (1, 3, 5, and 7% w/w) by incorporating it into the matrix network. The physico-chemical, thermal, mechanical, and antimicrobial properties of the cinnamon biopolymer films were obtained using dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transmission infrared spectroscopy (FT-IR), water contact angle (WCA) measurement, thermogravimetric analysis (TGA), mechanical testing, and antimicrobial testing, respectively. The results showed that the addition of cinnamon nanoparticles to the film improved the morphological, mechanical, thermal, wettability, and antibacterial properties of the nanocomposite films. The cinnamon particles were successfully reduced to nano-sized particles with an average diameter between 1 nm and 100 nm. The hydrophobicity of the film increased as the concentration of cinnamon nanoparticles incorporated into the seaweed matrix increased. The tensile and thermal properties of the cinnamon seaweed biopolymer film were significantly improved with the presence of cinnamon nanoparticles. The biopolymer films exhibited good inhibitory activity at 7% cinnamon nanoparticles against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Salmonella bacteria with inhibition zone diameters of 11.39, 10.27, and 12.46 mm, indicating the effective antimicrobial activity of the biopolymer film. The functional properties of the fabricated biopolymer film were enhanced with the addition of cinnamon nanoparticles.