BIOnTop’s research teams are pursuing various strategies to optimise biopolymers with a specific focus on protein-based coatings. European Bioplastics supports the BIOnTop project as consortium partner. 

Most sensitive foods are packaged in multi-layer composite films to ensure sufficient flavour, water vapor, and oxygen barriers to maintain products’ quality and increase its shelf life. However, most of these composite materials cannot be recycled. BIOnTop aims to develop fully recyclable and bio-based packaging materials in order to provide more sustainable packaging alternatives that offer optimised barrier properties and new end-of-life options. For this purpose, the project research currently focusses on polylactic acid (PLA)-based films. PLA is produced from renewable biomass and offers various end-of-life options, including mechanical as well as organic recycling (composting). Furthermore, PLA-based plastics can be produced on an industrial scale and already account for a considerable share of the global bioplastics production. The optical and mechanical properties of PLA films are comparable to those of conventional petrochemical polyester films. Yet, they are less suitable for fresh products with a medium to long shelf life due to lower oxygen and water vapour barrier properties. In order to achieve better barrier properties, PLA-based films can be modified by new coating technologies. 

To this end, BIOnTop’s research teams are pursuing various strategies to optimise biopolymers with a specific focus on protein-based coatings. The research builds on the results of a number of previous EU research projects in this field, namely Wheylayer and Thermowhey – two completed projects that were able to show that certain biopolymers are very well suited as coating materials to provide sufficient barrier properties for different types of packaging such as trays and blisters. For example, it has been shown that trays coated with whey protein have improved oxygen barrier properties to meet the requirements of modified atmosphere fresh meat packaging.   

Within BIOnTop, these new coating technologies are being further developed by the research group for Biopolymer Processing and Functionalization BPF headed by Dr Corina Reichert at the Sustainable Packaging Institute SPI of the Albstadt-Sigmaringen University (ASU). Her team works on the development of coatings made from bio-based materials such as fatty acids and proteins. Thermoplastic PLA films are coated with whey protein and a surface functionalization by an innovative fatty acid grafting technique is performed to make the film water repellent and to decrease the water vapor transmission. A protein coating layer is used to provide sufficient reactive groups for the fatty acids to be coated onto the PLA film. Additionally, the protein coating increases the oxygen barrier properties of the films. If successful, the developed bio-based multilayer films will be scaled up to pilot plant and industrial scale, and the