Recent advances in polymer-metallic composites for food packaging applications

Abstract

Background: The use of metallic micro- and/or nanoparticles as inorganic fillers for the improvement of polymer properties is an active trend. This has led to the development of polymer-metallic composites with high potential to be applied in food packaging, due to the enhanced antimicrobial, gas barrier, light-blocking and antioxidant effect in addition to the polymer intrinsic properties. The increasing number of investigations of novel polymer-metallic composites with promising potential and/or already applied as food packaging has raised concern over their efficacy, but also toxicity and environmental impact. Scope and approach: In this review a critical evaluation of current investigations on polymer-metallic composites, as food packaging options, is assessed. This evaluation emphasizes the enhanced properties provided by the metallic fillers onto the polymer packaging itself, and indirectly in food shelf life, safety and quality. Moreover, awareness regarding the toxicity and environmental impact is also evaluated and related to the migration behaviour. Key findings and conclusions: Without question, the addition of these type of fillers has the enormous potential to enhance the package properties and, therefore, the food shelf life. Usually, their addition is made alone or in complementation with other fillers allowing a broad spectrum of enhanced properties in the composite film. Despite the advantages, special attention must be paid to the migration form of the filler, in the ionic or the particulate form, that is related to the toxicity and environmental impact of such materials. In overall, the strengths and weaknesses are critically organized, allowing guidance decisions on the implementation of such materials in food packaging.