Plant-based micellar proteins as an alternative to petrochemical-based polymers
An important function of food packaging is to protect the contents from external influences such as oxygen and water vapor. In many cases this can only be achieved by combining different materials into multilayer laminates. The objective of the Mizellenkleber project is to replace petrochemical-based polymers, such as ethylene vinyl alcohol copolymer (EVOH), that are used as oxygen barriers in conventional packaging with materials made of sustainable raw materials.
Micellar protein adhesives have excellent barrier properties
Proteins have good barrier properties against oxygen. A special protein precipitation process enables the recovery of micellar protein structures. The Mizellenkleber project successfully developed a process for recovering micellar protein structures from leguminous plants (lupines and soy beans) and from residues from plant oil production (sunflower and rapeseed press cake). It has also been demonstrated that the protein-based adhesive formulations can be processed using the machinery used for packaging manufacture.
Biobased micellar protein adhesives offer unique adhesion and barrier properties
It has thus been possible for the first time to combine adhesive and barrier properties in a biobased material. Such barrier adhesives have not hitherto been available based on sustainable raw materials or oil-based materials. The use of the barrier adhesive results in significant packaging material savings, enables the development of new biobased packaging systems, and hence makes an important contribution to the sustainability of the food and packaging industries.
All the work was performed in close collaboration with the Technische Universität München (TUM, Department of Food Packaging Technology) and the adhesive manufacturer Jowat SE.
Another ongoing research project (Bioactive Materials) is investigating the use of the micellar protein adhesive on alternative substrates and also the mineral oil barrier of the protein-based adhesive. The project is being undertaken in collaboration with 18 partners from industry and R&D organizations. The aim is to suppress the migration of mineral oil from recycled paper using the micellar protein adhesive, so enabling paper to compete as food packaging.