Green biomass as a sustainable source of protein

The food industry is increasingly focusing on sustainable products. Proteins from green biomass are a promising option, as a research team involving the MLZ has discovered. These can be used, for example, as stabilisers in emulsions, such as in plant-based alternatives to yogurt, milk, ice cream, or cheese.

Dr. Theresia Heiden-Hecht (left) and Maren Müller (right) from Forschungszentrum Jülich at MLZ discovered in their study that proteins from biomass are suitable as stabilisers for emulsions. © Astrid Eckert, FRM II / TUM

Dr. Theresia Heiden-Hecht (left) and Maren Müller (right) from Forschungszentrum Jülich at MLZ discovered in their study that proteins from biomass are suitable as stabilisers for emulsions. © Astrid Eckert, FRM II / TUM

Sustainable and environmentally friendly living is becoming increasingly important in many areas. In the food industry, the development of resource-saving products is also gaining attention. This includes plant-based products, the use of agricultural byproducts, and the circular economy concept. Green biomass combines all these approaches because it is often an agricultural by-product that can be put to good use.

One application is stabilising emulsions as an alternative to animal milk products. As lead author Maren Müller from Forschungszentrum Jülich at MLZ explains: “The main source of emulsion stability is the interface where oil and water directly meet. For an emulsion to remain stable, proteins must accumulate at this interface. There, they ensure that small, evenly distributed oil droplets form.” Usually, animal proteins are used for this purpose. For this reason, the research team used small-angle neutron scattering (SANS) and X-ray scattering (SAXS) experiments at the KWS-X instrument at the MLZ to investigate whether selected proteins from green biomass are also suitable as stabilisers for emulsions.

The alfalfa plant examined whose biomass was used for protein extraction. © Karin Jähne / Adobe Stock

The alfalfa plant examined whose biomass was used for protein extraction. © Karin Jähne / Adobe Stock

Crop and aquatic plants as stabilisers

The crop alfalfa and the aquatic plant duckweed were used to study proteins from green biomass. Alfalfa can bind nitrogen from the air with the help of bacteria, which means it requires little fertiliser and is therefore a sustainable source of protein. Duckweed grows very quickly, has a high protein content, and is also suitable as a sustainable source of protein due to its use in recirculating systems and vertical farming.

The researchers used SANS and SAXS to investigate the structure of the proteins and their behavior at oil-water interfaces. The results are promising: “Our emulsions showed good stability. The oil droplets were small and evenly distributed, comparable to emulsions based on whey protein,” says Dr. Theresia Heiden-Hecht from Forschungszentrum Jülich at the MLZ. Both protein solutions stabilise the oil-water interface by greatly reducing the interfacial tension and achieve a performance comparable to that of widely used animal proteins. Proteins from green biomass thus represent a sustainable plant-based alternative for stabilising emulsions.