02/19/2025

New packaging for sensitive food: biobased and recyclable

Hochschule Albstadt-Sigmaringen

Consumers are familiar with transparent packaging with a protective atmosphere from the retail trade, mostly as packaging for meat, sausage and cheese products. These are now also used for vegetarian and vegan products. The advantage: the gas mixture contained inside provides a germ-inhibiting barrier so that food stays fresh and retains its shape and colour. However, their disadvantage is that they are only recyclable to a limited extent due to their multi-layer structure made of fossil raw materials. This means that they are lost to the material cycle after a single use. In packaging development, the aim is therefore to increasingly only bring recyclable packaging onto the market. Another development trend is towards plastic packaging with the highest possible bio-based content. However, bio-based packaging does not yet have a gas barrier that is sufficient for packaging sensitive food. Against this background, it is therefore necessary to develop a new type of packaging that is both virtually completely bio-based and recyclable.

This is where PLA4MAP comes in, a project commissioned by the German Federal Ministry of Food and Agriculture (BMEL) and funded by the Agency for Renewable Resources (FNR). Together, the project partners from the Fraunhofer Institute for Process Engineering and Packaging (IVV), Albstadt-Sigmaring University (ASU) and the Institute for Energy and Environmental Research Heidelberg (ifeu) have been pursuing the goal of developing a protective atmosphere packaging (MAP) made from fully recyclable raw materials since 2020. A prototype tray developed as part of the project successfully led to an almost completely bio-based four-layer barrier packaging, which is structured as follows:

Between two biodegradable top layers made of polylactic acid (PLA), a protein layer made of soy protein concentrate acts as an oxygen barrier, while a wax-hot melt layer acts as a water vapour barrier. The wax layer is obtained from sunflower wax, a by-product of the production of cooking oil. A PLA-based metallised sealing film acts as a lid.

As part of the research work, the task of the IFEU was, on the one hand, to derive parameters that would enable the recyclability of the newly developed PLA packaging to be assessed as simply and comprehensibly as possible. On the other hand, the institute evaluated the ecological sustainability of the finished product and compared it with conventional reference packaging.

The Fraunhofer IVV carried out the mechanical and solvent-based test recycling of the finished product in practice. This was followed by an evaluation of food law and an examination of the possible uses of the recyclate.

The results showed that the selection of raw materials used was successful: the multilayer tray composite fulfils all the required barrier properties and could be fully recycled if the sorting and recycling streams for PLA were sufficiently available in practice. If this could be established, the recyclate could be used to produce new, functional packaging.

Outlook:
The processing of bio-based materials into a barrier layer for plastic packaging is an innovative process that has so far only existed on a pilot scale. The high energy and cost input for the production and processing of PLA is currently still to be assessed as less sustainable compared to fossil-based packaging. It would be advisable to expand global PLA production and, above all, to reduce the weight of the packaging. The researchers see great potential for this to be achieved.

More information (in German): 

• Sustainability analysis (pdf)
• Recyclability (pdf)