Developing a pachyman/polyvinyl alcohol-polylactic acid bilayer film as multifunctional packaging and its application in cherry tomato preservation
Zexin Zhao, Yuan Xu, Pengpeng Zou, Long Xu, Jun Cai
Abstract
Polyvinyl alcohol (PVA) is a widely used biodegradable material, but its high solubility and water vapor permeability limit its applications in food packaging. To address this issue, bilayer films were developed based on the combination of blending and coating techniques in the study, which consisted of an inner pachyman (PM)/PVA blend layer and an outer polylactic acid (PLA) layer. Blending PVA with PM reduced the solubility and oxygen permeability of the film, and the blend matrix showed rapid self-healing capabilities. Loading of a thin PLA shell onto the PM/PVA layer improved the water resistance, tensile strength, stiffness and water vapor barrier of the developed bilayer films. The best overall performance of the bilayer film was achieved using 40 g/L PLA as the film-forming solution. Infrared spectroscopic and microscopic structure analysis revealed weak interfacial interaction of the bilayer film. Furthermore, this bilayer film showed a better preservation effect on cherry tomatoes compared with PVA, polyethylene, and PM/PVA films. The physicochemical quality of fruits could be effectively preserved for at least 10 days under ambient environment. It is anticipated that the bilayer film developed here serves as a promising candidate for food packaging materials to extend the shelf life.