Coating packing films with proteins
The oxidation of ingredients in foods results in the formation of off-odors, discoloration and loss of nutritional value. In order to prevent this, food packaging systems must present an effective barrier to oxygen and water. In general this can only be achieved using laminated films comprising different polymers.
Such materials possess the necessary barrier properties but are, however, very difficult to recycle because the individual film layers are welded together and difficult to separate. This problem can be overcome by coating individual polymer layers with proteins. Many plant and animal proteins, for example whey protein, have excellent barrier properties to water. By applying such a protein to a plastic film possessing oxygen barrier properties, a packaging material is obtained which is easy to recycle because the proteins can be easily removed using enzymes.
As part of a German-Brazilian research project the technology for the coating of packaging films with proteins will be further developed and adapted to specific Brazilian requirements (high humidity, temperature, and UV exposure).