Oxygen scavenging films for food application

The presence of oxygen causes deterioration of oxygen-sensitive foodstuffs. This leads to a deterioration of quality characteristics like colour, freshness and organoleptic properties. Due to the strong influence of temperature and exposure to light (photo-induced oxidation processes) this effect especially appears in transparent packaged chilled products (like sausages). Therefore, it is necessary to reduce the oxygen content in the headspace of the package. One possibility is the use of modified atmosphere packaging (MAP). But even at optimised processes the residual oxygen-concentration is up to 0.5 – 2%. To reduce this destructive oxygen, the additional use of oxygen scavengers becomes more and more attractive. Fraunhofer Institute for Process Engineering and Packaging worked together with industrial partners on an improvement of the kinetics of oxygen scavengers. In the AiF-funded project “Optimisation of transparent packaging materials with iron-based oxygen-scavengers for chilled products” (Nr. 15555N) the kinetics of oxygen-scavengers should be improved. Background of this was that the systems that are already available at the market do not work fast enough at low temperatures (5 °C). Therefore the aim of the project was to incorporate the oxygen scavenger into the packaging material and thus achieving better quality preservation and longer shelf-life of the chilled food. It could be shown that integrating the masterbatch SHELFPLUS® 2500 (SP2500) in a polymer (EVA) with high oxygen permeability resulted in higher oxygen consumption. Comparisons of the oxygen consumption of sausage and film showed that the use of the multilayer film PE/AL(SP2500; EVA) in combination with the food (exposed to light) resulted eight days earlier in a total consumption of the oxygen than storing the sausage without active film. This leads to a certain protection of the sausage.