The sound of a juicer at DTU Food could make a random visitor think that a nice staff get-together is being held. This is not the case when the sound comes from the Microbial Biotechnology and Biorefining research group. Here, the sound of a juicer is the sound of biorefining research. In the InnoGrass project, researchers are studying whether it is possible to extract proteins from green biomasses and use them as food ingredients.
“The first step in the extraction process is to run the green biomass through a juicer. We can extract proteins from the green juice,” says Peter Ruhdal Jensen, Professor and head of the research group at DTU Food.
The InnoGrass project started in 2019 and stands on the shoulders of similar research into the extraction of proteins from green biomasses for use in animal feed. Landbrug & Fødevarer F.m.b.A., SEGES is one of the InnoGrass partners, and it has also participated in the previous grass protein projects, says Erik Fog, national specialist at SEGES.
“Overall, we wanted to examine whether it was possible to meet the EU’s ambition that we’re to become self-sufficient with locally grown protein for feeding livestock, and thus avoid importing soy proteins,” says Erik Fog.
Virgin forests are cleared away
According to a press release from the European Commission in 2019, the EU imports approx. 14 million tonnes of soybeans, which are used as a source of protein in feed for animals—including chickens, pigs, and cattle—as well as for dairy production. According to Aarhus University, Denmark imported approx. 1.8 million tonnes of soy in 2018, with 1.7 million tonnes being so-called soy meal, which is a residual product from soybeans—after the oil has been squeezed out—and which is then used for, for example, feed. These imports put Denmark in 6th place among the largest soy meal importers in Europe. Aarhus University estimates in a report that the vast majority of Danish soy imports may come from productions in South America, where forest areas are cleared away for soy production, which impacts both biodiversity and climate.
“Clearing away forest to cultivate soy isn’t very climate-friendly, seeing that an area with soy plants can’t capture and store as much CO2 as a corresponding area with virgin forest,” explains Erik Fog. He adds that the soy must also be transported halfway around the world, which also results in carbon emissions, although to a lesser extent than the deforestations.
According to Aarhus University, it is estimated that deforestation in the tropics alone accounts for 20 per cent of global greenhouse gas emissions and that it is globally responsible for almost a third of man-made greenhouse gas emissions.
Grass proteins can replace soy
This makes the extraction of grass proteins interesting, and— through the other projects—SEGES and Aarhus University have contributed to showing that protein extracted from clover grass by means of biorefining can be used as feed for both pigs and poultry.
But there are other advantages to cultivating clover grass, explains Erik Fog:
“It’s a crop that can be harvested up to four to five times a year. It captures carbon from the air and channels it down to the roots, where it becomes part of the mould, which thus acts as a carbon storage facility. Last—but not least—clover grass is a natural soil fertilizer, as bacteria in the clover can convert nitrogen in the air into nitrogen in the soil. This results in better yields completely without the use of artificial fertilizers. This means that we can reduce the production of fertilizers, which is an energy-guzzling process.”
Erik Fog and his colleagues have analysed the entire value chain for Danish grass production and are now implementing it in actual business plans. In addition, two demonstration plants have been constructed for treatment of the harvested grass. The InnoGrass project is the next natural step in also utilizing the green biomass proteins as food ingredients for humans— and thus create products of higher value and with better financial returns—instead of just feeding pigs with them.
Strict requirements for grass proteins
This leads us back to DTU Food, where the squeezed green juice is subjected to many biorefining and food safety processes, trials, and studies.
“The actual extraction of protein can be done in different ways,” explains Professor Peter Ruhdal Jensen and elaborates:
“One method is simply to increase the temperature so that the proteins precipitate as sediment. Another is to lower the pH value of the green juice. The choice of method depends on what the protein is to be used for.”
Peter Ruhdal Jensen says that the researchers are therefore also examining the functionality of the extracted proteins.
“This may be whether the proteins have gel-like or frothy properties and can thus replace egg whites or milk proteins. These are interesting properties for food producers,” says Peter Ruhdal Jensen.
It is also important to know whether humans can absorb the proteins at all as a food ingredient, and the researchers are therefore also examining the digestibility of the proteins.
“We use an in vitro model that simulates human digestion in the test tube. This enables us to see to what extent the proteins from the green biomass can be expected to be broken down in the intestine, or whether they just pass straight through,” says Peter Ruhdal Jensen.
The grass is masked
As there are strict requirements for having the proteins approved as a food ingredient for humans, the researchers must also examine any unwanted substances such as toxins and allergens. Not to mention taste, colour, and aroma! Here, the researchers are working to mask the origin of the protein. So far, they have succeeded in both transforming the proteins into white powder and reducing the taste and smell of grass—and even making a variety of food products with the powder!
But what does grass protein in foods have to do with the climate, you might ask yourself. Peter Ruhdal Jensen explains it like this:
“It’s about what the proteins from green biomasses displace. If they can replace animal proteins from, for example, beef cattle, a great climate gain can be achieved. We can then skip the cow in our protein production. This means that we can reduce our demand for animal proteins—which are produced by animals requiring feed and water—and which are behind large emissions of the greenhouse gas methane.”
Before proteins from grass and other green biomasses can enter the market as a food ingredient, researchers must have obtained all the documentation required before the EU approves that the proteins can be consumed by humans. Peter Ruhdal Jensen and his colleagues will use a shortcut and submit an application for approval of alfalfa-extracted proteins as a food ingredient, as alfalfa is already today approved as a dietary supplement. This may make the approval process a little easier. The professor expects to be able to submit this application this year.