Extruded polymer films for optimal enzyme-catalyzed oxygen scavenging

Sammendrag

The use of enzymes as oxygen scavengers has a great potential in the food packaging industry. Enzymes can be incorporated in to a coating layer that can be applied directly on to the packaging material. For the system to be fully functional, there is however a need for the packaging to have some barrier properties, to be sealable through heat, and to ensure low or no migration of the active coating to the food. Various combinations of polypropylene (PP), poly (lacticacid) (PLA) and low density polyethylene (LDPE) were extruded on to board coated with the oxygen-scavenging enzyme. Properties such as oxygen- transmission rate, water-vapor transmission rate, heat-sealability, migration and oxygen scavenging capacity were evaluated. All combinations of extruded material resulted in a packaging material able to scavenge the oxygen at both 84% and 100% relative humidity. The greatest decrease in oxygen concentration of the head space of air-tight chambers was achieved with the material extruded with PLA on at least one side. It was found that the extruded plastic is necessary in order to meet the EU directives on migration from food packaging materials of not more than a total of 10 mg/dm2 material. All plastics were heat sealable against themselves but not against any of the other plastics and only LDPE adhered strongly to the enzyme-containing coating.