According to a recent German Society for Packaging Market Research survey, rising demand for composite films is matched by an increasing need for thermoformable composites, with demand for products in trays expected to increase from 76,497 tonnes in 2009 to 93,158 in 2014.
The Fraunhofer Institute for Process Engineering and Packaging (IVV) in Freising said in a recent statement: “Researchers are working hard to replace EVOH [an effective barrier material used in transparent films] in thermoform composites with a barrier layer based on whey protein. The additional application for whey protein would likewise conserve resources and reduce the emission of carbon dioxide into the atmosphere,”
Dr. Klaus Noller from IVV told FoodProductionDaily.com this research move was separate from the EU-funded Wheylayer project: “Thermoformability was not the intention for the first development, but is something we are working on now. The first results are encouraging but at the moment we do not have a solution for thermoformability. But if we want to replace EVOH, and we do, then we have to supply this property.”
Polymeric separation difficulty
Asked whether the move was prompted by the difficulty of separating polymeric structures of thermoformable composites for recycling, he said: “This problem is, in general, valid for all kinds of laminate. It’s not focused on EVOH. The problem is that is almost impossible to separate the monolayers, but the degradation of the whey layer gives us the possibility to separate the layers.”
Transparent multi-layer films are used to protect foods from contamination, and to minimise oxygen ingress, packaging firms normally use ethylene vinyl alcohol (EVOH) copolymers as barrier materials.
But the same packaging market research (detailed above) estimated that more than 640km2 of composite materials using EVOH as a barrier layer would be produced and used in Germany in 2014.
Thus there was a strong impetus to develop a sustainable packaging material that is both economical to produce (since EVOH is relatively expensive) and environmentally friendly, IVV said.
Through the three-year ‘Wheylayer’ project that began in November 2008, IVV has helped developed economically viable whey protein-based polymers instead of petrochemical-based polymers; it claims that whey naturally extends product shelf life and is environmentally friendly, where EVOH cannot be recycled but only burnt.
Asked when he thought the first Wheylayer-based composites would appear on the market, Noller said IVV was in the industrialization phase with one customer: “I think the first application will be with tubes, because one of our project partners now has a pilot line to apply Wheylayer on top of films he uses to produce his tubes. This will not be a big market at the beginning, but first you have to check that it works and so on.”
Whey is a co-product of cheese, and Noller also had no doubt that that there would be a readily available input stream to fuel whey-based polymer production if demand took off.
He said: “I’m sure in Europe it would be quite easy, but we only have the numbers to hand in Europe. I don’t know how it looks in other continents.”
Wheylayer: how was it developed?
- IVV researchers purified sweet whey and sour whey to produce high purity whey protein isolates, which they then mixed with bio-based softeners and other additives to perfect a film formula.
- If too many softeners were used then the barrier effect (against water and oxygen) decreased, the scientists found, while there was also a need to develop an affordable means of applying whey protein coatings to plastic films to produce multilayer structures.
IVV said firms choosing to switch from EVOH to whey proteins need only make minimal plant modifications; a patent for the technology is owned by the IVV’s industrial project partners.