New method extracts more protein from seaweed
Proteins in sea lettuce could become a promising alternative to meat and other protein sources. Proteins are often tightly bound, but now researchers have found a way to extract them that is three times more efficient than previous methods. The advance opens a door to seaweed burgers and protein smoothies from the sea.
The so-called protein shift is a way to reduce the climate impact of food production while ensuring a nutritious diet for all. Many alternative protein sources are mainly land-based, such as pea, soy and mushroom proteins, while the vegetarian protein found below the sea surface is still an unused source.
In the CirkAlg project, a research collaboration between the University of Gothenburg and Chalmers University of Technology, a newly published study led by the Chalmers research team, shows a new way of extracting proteins from sea lettuce, so that it’s possible to extract three times as much protein as was possible with previous methods.
“Our new method is an important breakthrough, as it means that it can be more economically viable to extract the proteins from sea lettuce, something that is already done with peas and soya today,” says João Trigo, PhD in Food Science at Chalmers.
Increase protein content of seaweed
In addition to the new extraction method, which allows more protein to be extracted from the sea lettuce, the researchers are also looking at ways to increase the protein content of the seaweed itself. By growing in nutrient-rich process water left over from the seafood industry, the protein content of the sea lettuce increases significantly. The process water becomes a resource where the seaweed purifies the water and at the same time you get seaweed with high protein content.
“Sea lettuce has proven to be a very promising seaweed species for cultivation in process water, as both growth and protein content increase significantly after just a few days in the water. The increased protein content of the seaweed is important, as we can then extract even more proteins with the new extraction method,’ says Kristoffer Stedt, researcher at the Department of Marine Sciences, University of Gothenburg.
Green powder with umami flavour
In addition to essential proteins, sea lettuce contains several other important nutrients, such as vitamin B12 and the same type of omega-3 fatty acids found in oily fish, such as salmon. The new seaweed protein ingredient may therefore help to meet more nutritional needs than, for example, soya protein. The proteins from the sea lettuce are concentrated into a dark green powder that can be blended into smoothies, for example.
“It has an umami taste with a slight saltiness. I'd say it's a great flavour enhancer in seafood dishes, but the possibilities to explore are endless. Why not in protein smoothies or as a seafood burger? says João Trigo, PhD in Food Science at Chalmers University of Technology.
“We will need to find and combine intakes of many more different sources of protein than are currently available in our diets to fulfil sustainability and nutritional requirements. Seaweeds are a good complement to many of the products already on the market. We need all these solutions and so far, the sea-based opportunities, the so-called blue proteins, have been overlooked,” says Ingrid Undeland, Professor of Food Science at Chalmers University of Technology and coordinator of Cirkalg.
Text: Karin Wik & Annika Wall
In the CirkAlg project, researchers from the University of Gothenburg and Chalmers University of Technology have explored the possibilities of developing processes that can create a new, blue-green food in Sweden, and utilise sea lettuce and other algae species as promising protein sources.
To the CirkAlg webpage.
More about the study
The study Anew method for protein extraction from sea lettuce (Ulva fenestrata) via surfactants and alkaline aqueous solutions has been published in the journal Food Chemistry.
The authors of the study are João Trigo, Sophie Steinhagen, Kristoffer Stedt, Annika Krona, Simone Verhagen, Henrik Pavia, Mehdi Abdollahi and Ingrid Undeland.
The researchers were active at Chalmers University of Technology, University of Gothenburg and Rise - Research Institutes of Sweden at the time of the study.
