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Protein Mining of Cereal side-streams Exploring Novel Technological Concepts

Periodic Reporting for period 2 - PROMINENT (Protein Mining of Cereal side-streams Exploring Novel Technological Concepts)

Reporting period: 2017-01-01 to 2018-10-31

CONTEXT: There is a global need to increase dietary intake of plant protein, from sustainability, food security and health perspectives. Wheat and rice are globally the most cultivated grains after corn, and their processing side-streams offer a large under-exploited raw material potential.

OBJECTIVES: The objective of PROMINENT was to develop techno-economically feasible and sustainable technologies for concentration of proteins from solid and liquid cereal side streams and for improvement of protein ingredient functionality to enable new sustainable food concepts that meet consumer demands.

CONCLUSIONS: Three new high protein ingredient prototypes were developed from wheat and rice processing side streams. Using on membrane and expanded bed adsorption chromatography, we developed two ingredient prototypes based on soluble wheat side streams, where protein content was about 50% or over 90%. We also developed a functionalized rice endosperm protein by modifying the upstream of the fractionation and use of enzymes. Rice and wheat bran hybrid ingredients high in protein and dietary fibre were functionalized for use in crackers and yoghurt-type foods. The new protein ingredients were shown to be environmentally more sustainable than animal based protein. The results demonstrate the potential of side stream use as source of new plant protein-based food ingredients, and to thereby increase food system sustainability.
Dry and wet fractionation technologies were developed for solid and liquid wheat and solid rice side streams, and scaled up to deliver protein isolates and concentrates in kilogram scale for modification and product application studies. Four ingredient types were selected for detailed techno economic analysis: Enzymatically modified rice endosperm protein (78% protein) with improved techno-functional properties, wheat protein isolate from soluble side stream (around 90% protein), protein-enriched wheat bran fraction (32% protein) and wheat protein concentrate from soluble side stream (over 50 % protein), with dietary fibre as the other major component.

Rice endosperm protein was enzymatically modified to improve its functionality and applicability. Two new rice endosperm protein ingredient concepts, one partially and another fully soluble were developed and tested in food models. Solid raw materials were dry fractionated by milling and air classification and enzyme-aided aqueous processing, but did not deliver ingredients with the target 40 % protein content and acceptable yield. However, dry fractionated wheat and rice brans, enriched in protein, were used in lab scale application development to produce crackers and gels rich in dietary fibre and protein. Use of phytase improved gel formation properties of the hybrid ingredient considerably. For liquid wheat processing side streams (C-starch), membrane and chromatographic technologies were scaled up to pilot scale to produce a soluble wheat protein concentrate with over 50% protein and also soluble dietary fibre. Over 90% protein content was reached in soluble wheat protein isolates, produced by one-step elution in expanded bed chromatography. Bench scale processing further included concentration and spray drying, and yielded kilograms of quite pure protein.

Rice endosperm protein and C-starch ingredients were tested for use in beverage, cake and pasta. There is need for further development both with respect to functionality and especially taste. In particular, the protein ingredients separated from soluble wheat side stream were highly soluble and showed interesting functionalities for food applications, but their color and taste need further consideration in terms of application development. Some promising results were obtained, pointing out that the side-stream-based ingredients can be applied at least as a biscuit ingredients or as a raw material for meat analogues.

For techno-economic evaluation a funnel approach was used to first identify 75 process and then gradually come up to four economically most promising and technically possible new protein ingredient concepts. Light-TEA (techno-economical assessment) showed promising economics for three concepts and identified improvement needs in others. Process simulation, equipment vendor quote/literature based economic analysis as well as iterative business and partnership canvas approach were used for the more detailed case studies. The evaluated production costs were below the reference product market price values, and thus all four cases seem feasible. Value creation was identified in the partnership cases studied, but more ingredient users would be needed, as the demand of the project partners in the cases studied was low.

Safety was assessed from many points of view since the side-streams used as raw material are currently not used for food. Some microbiological issues need further work. Environmental life cycle assessment showed that concentration and isolation of proteins from C-starch side stream and new uses of modified rice endosperm protein are promising ways to produce protein ingredients that are environmentally more sustainable than animal protein sources. Process optimization may improve the sustainability of these new ingredients further. Still, one has to remember that environmental impacts are reduced only when animal products are replaced with these novel plant proteins, not if plant proteins are consumed on top of our current diets.

Social Life Cycle Assessment (S-LCA) analysis was made considering the UN Sustainable Development Goals. S-LCA was developed as a new tool for companies to identify risks for social impacts of their actions as well as hot spots in the production. This study was conducted at a general level and pointed out risks for different social impact categories (such as Fair salary) for average European wheat and rice protein production. A Social Impact Risk Map tool was also developed and tested to support company managers in SDG management.

The project has 6 scientific papers in pipeline. 4 MSc theses were produced. Dissemination included web page updates, 3 press releases, 2 project leaflets, 12 videos, table-tops in 2 food events, 9 congress presentations, 5 trade magazine articles and the collaborative seminar “ New Protein Mining Technologies” with 5 PROMINENT presentations in Rotterdam in April 2018.
We performed substantial investigation of technologies for protein separation, concentration and isolation from cereal side-stream matrices, as well as techno-economic and social and environmental sustainability assessment with new methods. These will benefit industry, stakeholders, policy makers and scientific communities for valorization of side streams. Three new high protein ingredient prototypes were developed, and protein-fibre hybrid ingredients with enhanced functionality were demonstrated in gel and cracker food models. New enzymatic modification methods were proven useful. Three new concepts were shown to be economically feasible and can also create cash flow. The new protein ingredients were shown to be environmentally more sustainable than animal- based protein. The results thus pave the way towards using side streams for new plant protein-based food ingredient production to increase food system sustainability.