Search for alternative and sustainable proteins from plants, microorganisms and fungi

Cheese without cows

Cow's milk is an important source of protein in the Western diet, but its production has a significant impact on the climate and animal welfare. Demand for animal-free dairy products is increasing and there are already a lot of vegan products on the market. But vegan cheese is still difficult to make. Dairy products based on plant-based proteins do not have the same taste and structure as cheese from milk. Therefore, WUR is investigating the possibilities to make sustainable, nutritious and flavourful cheese using microorganisms.

“Cow milk contains caseins. These proteins form clusters (micelles), and it’s these that create the gel-like structure of dairy products”, says Etske Bijl, Food Quality and Design researcher. Bijl and her colleagues intend to use yeasts to produce casein, an animal-free route to produce protein with the same nutritional value and properties as protein from cow’s milk. They hope it will then be possible to make cheese that is just like ‘real’ cheese. Bijl: “The vegan cheeses currently available on the market are, for example, made from starch or compressed nuts. These may also be delicious, but they aren’t the same as cheese.”

The plan is to build the genetic code for casein into yeasts, so that they produce cow milk protein. The genetic code is created in a lab, so no cows are involved. “Then we’ll look whether the yeasts do actually make the protein”, says Bijl. “And whether they make modifications themselves, something that yeasts sometimes do. The question is whether it has to be 100% identical with casein from a cow, and whether a protein that is slightly different still has the desired properties, such as the forms of the micelles as otherwise you still don’t have the right structure. These are things we still have to study.”

The researchers are working together with Those Vegan Cowboys. “We carry out the same kind of research in parallel. What’s unique here is that we share all the knowledge, something which isn’t usual in the industry. There are lots of start-ups working on similar studies, but they often protect their work, for example because they want to patent it. We are the first scientific project in this area. Our ultimate aim is to make vegan milk protein. We can achieve this more easily by working together.”

“If our project is successful, then the industry can develop new products using these proteins and take advantage of the increasing demand for animal-free dairy products.” But the question is how consumers will view a protein made by a genetically modified yeast, a GMO. “We are working together with WUR’s philosophy group to study how consumers regard GMOs, as it is often much more complex than simply being for or against it.” The researchers also talk to farmers regularly. Bijl: “In the first instance you would think that they wouldn’t be interested in it, as it possibly competes with their product. But we work together with agricultural innovation platform Brabant and see that small farms, often family farms, are thinking about the future. There are certainly farmers who are interested. They could, for example, produce the proteins themselves and make their own ‘Boerenkaas’ with it. We’re also looking for start-ups who can help make simple installations so that the farmers can do this themselves. A kind of microbrewery, but then for proteins.”

According to Bijl, if everything goes well, it will still be some time before the vegan cheese, with milk protein made by yeast, is on the market. “At present it still can’t be sold in Europe, because it’s a GMO product. We hope that our knowledge will also help to change the legislation. It’s already permitted in countries like Singapore and the US. Perfect Day makes ice cream from animal-free proteins, but it’s still very expensive.” In addition to legislation, there is also the question of whether the technology can be scaled up in an affordable and sustainable manner. According to Bijl: “We expect the process to be more sustainable than industrially produced casein that is obtained from milk. As yeasts don’t need much nutrition and are very efficient. We’ll calculate this once we know that the yeasts actually work.”

Improving the taste of pulses

In addition to animal-free dairy products, the industry and the consumer are also increasingly calling for more protein from pulses in products such as meat and dairy substitutes, as an alternative to animal proteins. But the taste of pulses is not optimal for this application. You can taste this in dairy substitutes in particular. “The taste is sometimes compared to cardboard”, says Laurice Pouvreau, Wageningen Food & Biobased Research.

The advantage of pulses is that they are a sustainable source of protein. “Crops such as peas and broad beans grow well in the European climate”, says Pouvreau. “Which means that we don’t have to import so much soy, for example. In addition, they have a relatively high yield and fix nitrogen in the soil.”

Pouvreau and her fellow plant and food scientists are working together on a project to breed pulses (e.g. by cross-pollination and genetic selection), so that they have better taste and other properties for use in food. “We know what causes the cardboard-like taste and through breeding we want to find existing varieties or develop new varieties that have a less unpleasant taste.” The researchers are also looking at other properties, such as soil type and the climate in which a variety grows best. Pouvreau: “Europe is diverse, and the climate and soil in Groningen are very different from those in the south of France, for example.” In addition, the crop must also be high yielding, as it must be financially attractive for farmers to grow pulses.

Unique to this project is the reverse engineering approach, according to Pouvreau. “First, we talk to food producers to determine the requirements with regard to taste and functionality of the proteins, and from there we go back again to the start: the seed. So we take a look at the whole production chain. With the ultimate aim to breed pulse varieties with the best taste and properties for meat and dairy substitutes.”

Fermentation helps combat protein shortage

A third example of alternative protein sources are fermented products (with bacteria or fungi) such as tempé and kimchi. The process of fermentation is centuries old but can be put to better use. For this reason Jasper Zwinkels, from Food Microbiology, studied whether fungal fermentation can improve the nutritional value of a product. He did this with rice and barley. Zwinkels: “We chose these because these crops are eaten in large quantities, also in low-income countries, and it’s precisely in these countries that people need a high-quality protein. Proteins from fungi do have a different composition to plant proteins. These protein sources come together in a fermented product, and this means they can form an amino acid composition that fits better with our nutritional requirements.”

Fermentation is as old as the hills. However, it has not been studied previously what this precisely does to the protein quality of the product. “This really surprised us”, says Zwinkels. “The method itself isn’t complicated. You take a substrate, like rice or barley, and grow the fungi on it.” And this is exactly what Zwinkels and his colleagues have done. The initial results are very promising: “We saw an increase in protein quality. There was 10% more microbial biomass after fermentation with fungi in comparison with the normal quantity after bacterial fermentation. Mycoproteins also have a better amino acid composition. Lysine, for example, is an essential amino acid that our body doesn’t make itself, so we have to obtain it from food. Lysine is present in high concentrations in meat, dairy and fish, but there is very little in grains. There’s a lot of lysine in mycoprotein.” According to Zwinkels this is very valuable for a lot of low-income countries, where grains, rice and root crops form the basic diet. “Fermentation is a simple way to make this more nutritious. All you need is a warm, damp place. It has advantages as compared to fermentation with fungi in bioreactors, which is expensive and more difficult to adapt to the location.”

Zwinkels believes that the study could mainly contribute to the formation of guidelines for good nutrition. “We haven’t developed a new method. But we demonstrate that using an existing method you can help combat protein shortages in a sustainable and affordable manner.”

Follow-up research is required to study how the fermentation process actually works. “At present, we have only looked at the amino acid ratio in products with and without fermentation”, says Zwinkels. “But we also want to study in detail exactly what kind of proteins are made by the fungi. Something that’s pretty difficult to study as the fungi are completely intertwined with the plant seeds.” Zwinkels also wants to study more fungus types and substrates to improve the amino acid composition for each product.