In recent years, plant-based protein sources have surged in popularity as an alternative to meat, especially as a way for individuals to reduce their carbon footprint. However, as Milena Corredig, Professor in Food Science at Aarhus University in Denmark, says, “the ideal situation would be if the sustainable and nutritious food was the preferred choice on its own merit." That's why her team recently used neutrons at ISIS to study a new potential plant-based source of protein: rapeseed.
Rapeseed is one of the most widely grown plants, and its cultivation is resilient to conditions as harsh as those in the Nordics. It's most commonly used as a source of oil in cookery, biodiesel, and mechanical lubricants. However, current processing methods don't use the entire plant, so Milena's research group has been investigating a different extraction process. This still provides oil, but also allows proteins to be extracted, which could become a valuable source of nutrition.
The protein is extracted by a very simple method: they gently mill the seed in water. Compared to the solvent-based techniques currently used for processing rapeseed, this is a much more sustainable method and produces higher-quality proteins.
However, it sacrifices some purity: whereas existing approaches produce protein isolates, the new process yields a composite mixture of molecules. Therefore, it's vital that researchers can learn to work with this complexity.
Milena and her team prepared a set of samples for studying at ISIS. They worked with ISIS instrument scientist Gregory Smith on the SANS2D instrument to conduct several Small Angle Neutron Scattering (SANS) experiments, obtaining key data. These results complement X-ray scattering data, obtained at Sweden's MAX IV facility in collaboration with Prof. Jan Skov Pedersen at Aarhus University.
Milena described the experiments as feeling like detective work, especially as it was the first time that the composite molecules have been studied. She says, “neutrons allowed us to build up a beautiful snapshot of the complexity of the system".
Despite having time to run relatively few tests on SANS2D, the team has already learned lots from their experiments. Their SANS results strongly agree with X-ray and electron microscopy studies, and they've “really broadened understanding of the protein structures", says Milena.
Following the success of this study, they now need to test these particles in a wider range of ways, to gain an even deeper understanding of their complex structures. Deuterium-contrast methods are a valuable tool in neutron scattering experiments, and Milena's research team is keen to develop their research with techniques such as those.
The demand for oil isn't going anywhere, so rapeseed will continue to be useful as a source of oil. However, this research could pave the way to new approaches for producing plant-based protein ingredients on a large scale, making better use of the entire plant.
In an ever climate-conscious world, the need for plant-based proteins is only increasing. Our food systems require significant transformation, with no universally 'best' solution. This requires researchers to explore many different available options. Alongside insect-based proteins and synthetic proteins, rapeseed proteins and other plant-based protein sources will be a foundation for the future of sustainable diets.
The full paper is available at DOI: 10.1016/j.foodhyd.2024.110770
