To minimize the amount of oxygen that penetrates the packaging of food products, companies typically use expensive, petrochemical-based polymers such as ethylene vinyl alcohol (EVOH) copolymers as barrier materials. Researchers around Markus Schmid, Fraunhofer Institute for Process Engineering and Packaging IVV, Freiburg, Germany, developed biodegradable whey protein layer. Their so called roll-to-roll method to manufacture a multilayer film for food packaging is a world’s first.
The researchers purified sweet and sour whey and produced high purity whey protein isolates. They tested a range of different modification methods in order to obtain suitable proteins with outstanding film-forming properties. To enable these proteins to withstand the mechanical loads involved, they were subsequently mixed with differing concentrations of various softeners and other additives, which were also biobased.
In a suitable, economically viable and industrial-scale method the whey protein coatings were applyed to plastic films. These were combined with other films using different technologies. The overall process produces multilayer structures with barrier functions which can be used to produce flexible, transparent food packaging materials.
Image: © Fraunhofer IVV