Miriam Meister

Green protein without taste of cowshed

Tuesday 21 Sep 21


Peter Ruhdal Jensen
Professor, Head of Research Group
National Food Institute
+45 20 85 56 01

About production of green biomass

  • Grass is easy and inexpensive to produce in Denmark.
  • The amino acid composition in grass protein is similar to that found in protein sources such as soy, eggs, and whey.
  • However, grass protein production has a considerably smaller impact on the environment and climate.

Researchers from DTU Food have developed a technique for extracting protein from green biomass without unwanted off-flavour.

Cows like grass to taste like grass. However, if people are to eat sustainable protein extracted from green biomass such as ryegrass and alfalfa, it is crucial that it does not have a taste profile which some people describe as ‘cowshed’.

Food producers can use aromatic ingredients to camouflage the protein powder’s off-flavour, or they can use techniques to remove it from the powder.

In fact, researchers in this field describe the removal of the unwanted taste as ‘The Holy Grail’. Nonetheless, it seems that DTU Food may have found it: DTU Food’s researchers have succeeded in removing most of the hay smell and cowshed taste by using a supercritical CO2 extraction system to treat protein mass made from alfalfa.

A supercritical CO2 system works by bringing CO2 into a supercritical phase by increasing the gas to above 70 bar pressure and above 33°C. In this phase, CO2 constantly switches between being in the gas phase and the liquid phase. This enables the gas to penetrate particles—such as the green protein—and extract flavours and aromas from the protein without altering its functional properties.

Replaces soy protein

The technique is actually not new. It has been used safely for more than half a century to remove, for example, caffeine from coffee and aromatics from hops. Once the protein from the green biomass has been treated, it can be used in foods and replace the soy proteins that have been the primary source until now. Swapping the protein sources reduces the climate impact of the foods.

Until now, DTU Food has only had a small-scale supercritical CO2 plant at its disposal, which the researchers have used to experiment with finding the exact settings needed to make the power neutral in terms of taste and fragrance.

With funding from the research infrastructure FOODHAY, DTU Food has now purchased a larger plant that can handle much greater amounts of protein powder. DTU Food sends the treated powder to its project partners, which incorporate it into various food products with a lower climate footprint.

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