Development of a bilayer starch/chitosan film for food packaging applications

Abstract

Food packaging plays a crucial role in preserving food quality throughout distribution. This study developed a starch/chitosan bilayer as a bio-packaging material. Compared to previous studies, the characterization of film-forming dispersions has been significantly improved, demonstrating their suitability for producing high-quality bilayer films. After preparing and characterizing the starch and chitosan dispersions and the resulting films, the bilayer was obtained by depositing the chitosan dispersion onto a pre-formed starch film. The bilayer was analyzed using microscopy, contact angle measurements, Fourier Transform Infrared Spectroscopy, tensile strength tests, thermogravimetric analysis, gas permeability assessments, total solids, and solubility tests. Results show the bilayer possesses mechanical and physical properties comparable to commercial plastics, even after refrigerated or frozen storage. Notably, it exhibited high hydrophobicity, with a contact angle of 100°, and good thermal stability, with only 10 % mass loss up to 200 °C, making it suitable for domestic oven use. Additionally, the bilayer is entirely impermeable to carbon dioxide at atmospheric pressure and shows a permeability of 15.16 barrer under a transmembrane pressure of 5 bar, contributing to extended food shelf life. It also remains insoluble in water for at least 24 h at room temperature and resists acidic and alkaline environments, maintaining integrity with wet or reactive foods. These findings suggest that the starch/chitosan bilayer could be a viable, eco-sustainable alternative to conventional plastics, offering promising applications in the food sector. This study contributes to the advancement of sustainable food packaging through the development of a durable, environmentally friendly bilayer material with industrial potential.