nutrition - proteins - plant protein - biomass - biorefinery - agro-industrial chains
In 2013 a new STW research programme was started on sustainable protein recovery. This STW Protein Programme consisted of five sustainable protein technology projects, which aimed at developing innovative methods to extract proteins from plant leaves, microalgae and insects to meet the increasing demand for food proteins for humans and livestock. The aim of the additional STW-project ‘Meer en Beter Eiwit’ was to summarize and evaluate the main results and conclusions of these five projects. Besides, some more recent additional insight on protein extraction was supplemented. Project partners including WUR, knowledge institutes and industry were interviewed to obtain their opinion on the project performed and future research needs.This has led to a vision document that gives direction to future research in the field of protein and technology.The approach of this project was to study the topic from start (biomass) via technology to finish (product). It was further put into a larger perspective, looking at the entire chain. When relevant, additional aspects such a soil quality and global protein demands were included.Biomass choice. When choosing a particular protein-recovery technology,biomass selection is the first requirement. Much research is being done on new biomass. However, the use of existing raw materials and residual flows should not be neglected.By building on existing processes and chains, fast(er)implementation is possible. Traditional crops like grain are relatively dry, and the proteins are present in protein bodies. Therefore, they are more easily extracted and give high yields and purities. New, green crops still require a lot of development.Protein streams in the world Protein-rich sources, like soybeans, rapeseed, maize and wheat are being consumed by both humans and animals.The crop with the largest production volume in Europe is is wheat, followed by potato, maize and barley. Together these four crops cover about 85% of the production of protein crops. Worldwide, maize is the largest crop. By far, the largest amount of proteins is being used in feed (>75%),followed by food consumption. Only a limited amount of proteins is isolated for specific use, for example as emulsifiers in different food formulations. An even smaller amount is used for application in chemicals or materials.Protein purity and functionality. Much research from the past focused on obtaining pure protein, e.g. RuBisCo from green leaves or protein from potato juice. Such processes can be economically feasible if the protein produced has a specific functionality, which allows for use as a high-quality food ingredient. However,high purity is not always required to obtain a certain functionality. In such cases the use of less refined,functional fractions is an interesting alternative.Mild separation and fractionation. When purified components are replaced by functional fractions, less intensive separation conditions can be used.Dry separation of proteins yielding a concentrate could bean alternative to wet separation yielding an isolate. Energy consumption is less, and a more native protein can be obtained. Fractionation can also lead to more complete use of biomass, generating little to no side streams.Chain approach for economy and sustainability. Next, it is also important to include the possibility of complete utilization of the raw material and closing cycles.These latter aspects can make or break economic feasibility and sustainability in a process. Efficient and effective use of protein and nitrogen, while maintaining biodiversity, is the most important development point for sustaining life on this earth. Modern agriculture should further improve nitrogen and feed use efficiencies to increase sustainability. Program evaluation. Next to conclusions on the content of the five projects, the evaluation also provides conclusions on the set-up of the STW/EZ programme on sustainable protein. Both academic and industrial participants acknowledged the added value of the link between fundamental research by a PhD and applied research by research institutes that was made in the project set-up. They also partly attributed the project successes to the multidisciplinary approach in the projects. The possibility within the projects to look at all aspects, and the ability to think anew on existing processes and develop new concepts of biorefinery greatly added to current scientific knowledge on protein extraction.