Photo: Ditte Valente

From seaweed to proteins

Friday 15 Mar 19


Charlotte Jacobsen
Professor, Head of Research Group
National Food Institute
+45 23 27 90 75

How protein is extracted

Extraction of proteins from Spinosum (Eucheuma denticulatum) step by step:

  1. The seaweed is soaked in water.

  2. Enzymes and some chemicals are added, causing the proteins to detach from the seaweed and seep into the liquid. 3. The seaweed (now free of proteins) is separated from the liquid in a centrifuge, so that extraction of the carrageenan can begin.

  3. The protein liquid is dried out, so that only the proteins remain.

  4. This method extracts 50-60% of the proteins in the red seaweed.

  5. The research is being financed by Karl Pedersens og Hustrus Industrifond and the Green Development and Demonstration Programme (GUDP).
Food researchers have invented methods for extracting proteins from seaweed. One of them is now being tested in a pilot plant at ingredient producer CP Kelco.

Flasks filled with seaweed have been a common sight in the laboratories at DTU Food for the past 3-4 years.

During this time, a research group headed by Professor Charlotte Jacobsen has been testing methods to extract proteins from seaweed. Three seaweed varieties have been tested, and researchers have discovered how to ‘open up’ the different varieties so that the proteins can be extracted.

“For two of the varieties, we can extract the proteins using enzymes. In the third variety, enzymes did not work at all. In this case we discovered that it was possible to extract proteins by making the pH value more alkaline,” says Professor Charlotte Jacobsen about the first step in the extraction process.

One of seaweed varieties being tested in the laboratory is the red Spinosum (Eucheuma denticulatum), which CP Kelco imports by the tonne to extract carrageenan. This is used as a stabilizer and thickener in everything from chocolate milk and meat products to toothpaste and face cream.

CP Kelco joined forces with DTU researchers to look at the possibility of extracting other resources from the seaweed in addition to carrageenan, reports Karin Meyer Hansen, Senior Manager in Product & Analytical Method Development at CP Kelco:

“Once we have extracted carrageenan from the seaweed, what remains is a waste product that we send to a biogas plant. It is of interest to us if the seaweed can be used for something else. If we can also extract proteins, we create greater value from the seaweed waste product. So we get more from our production and better utilize the resources.”

An unexpected benefit

The DTU researchers first tried to extract proteins from the waste seaweed from CP Kelco, but found that the protein yield was too low as a result of the carrageenan extraction. They therefore had to reverse the order.

“We had to find a different method, so that we could extract the proteins first. We now have promising results from the laboratory that show that extracting protein first does result in poorer quality carrageenan subsequently being extracted,” explains Professor Charlotte Jacobsen.

In fact, the protein extraction actually improves the carrageenan as a final product, reports Karin Meyer Hansen:

“During the extraction of proteins, the seaweed’s natural colour is also removed. This is an advantage for us, as many customers want a colourless carrageenan that adds nothing but texture to their products. So the more colourless and tasteless it is, the better.”

However, being able to extract proteins and the fact that the carrageenan is good quality is still not enough.

Vegetable proteins in demand

CP Kelco’s decision whether to begin extracting proteins from the red seaweed will also depend on whether the proteins have value. Can they be sold and used in the food industry?

Third Wave Nutrition is taking part in the project to test whether the seaweed proteins can be used in the dietary supplements and other protein products the company produces for users such as athletes and vegans.

"We must find new sources of proteins, and I think we will need all the alternatives we can discover. "
Professor Charlotte Jacobsen, DTU Food

Photo: Ditte Valente

“It would be revolutionary to get a new source of high quality vegetable proteins. We see proteins as being high quality when they have the right composition of amino acids, are uncontaminated by heavy metals or pesticides, and do not add a bad taste to our products,” says Henrik Schimmel, CEO of Third Wave Nutrition.

The seaweed proteins do not yet fulfil all these requirements, Third Wave Nutrition notes, but the company is ready to do more tests when CP Kelco produces proteins in its pilot plant.

The DTU professor agrees that more work is necessary to produce proteins of a quality acceptable for use in food.

“We’re still facing some challenges with proteins, and more work needs to be done before we see seaweed proteins in consumer products. But we have proven the general principle that it is possible to extract proteins from seaweed. In one seaweed variety we were able to extract up to 90 per cent of the protein content,” says Charlotte Jacobsen. She also notes that the world is waking up to the potential of seaweed:

“In light of the global population growth, we must recognize that not everyone can meet their protein needs through animal proteins. We must find new sources of proteins, and I think we will need all the alternatives we can discover. We have demonstrated that seaweed definitely offers some potential,” concludes Charlotte Jacobsen.

Photo: Ditte Valente
Three seaweed varieties have been tested as protein sources at DTU Food. Enzymes ‘open up’ the seaweed, making it possible to extract the proteins. The process leaves the seaweed gel-like and colourless. Professor Charlotte Jacobsen has achieved good results extracting proteins from seaweed. Photos: Ditte Valente.