Spirulina as a protein supplier?

Microalgae in food

With the world population, the need for protein-rich foods is also growing. A sustainable alternative to meat could be the microalgae Spirulina. Based on dry matter, it has a protein content of 63 percent, with soybeans it is, for example, 35 to 40 percent. So far, Spirulina is only in the form of powders, pills and capsules as a dietary supplement on the market or is used to obtain natural dye.

Scientists at the University of Göttingen have now tackled the question of whether the alga with the scientific name Arthrospira platensis is also suitable for the production of food. The so-called wet extrusion ("high-moisture extrusion") is a common method, for example, from soy protein to produce fibrous and bite-resistant products. Here, the vegetable proteins are boiled at high water contents and pressed by rotation of two screw shafts through a cooled nozzle. In this way, the meat-like texture of soy chips and soy nuggets.

The food technologists examined whether this process can be used to produce soy products with a different content of spirulina (10%, 30%, 50%) of basic products for meat alternatives and what influence technical parameters have on texture and taste. The conclusion: With low humidity, high speed of the screw shafts and high temperatures during the extrusion, it is possible to replace soy protein partly with spirulina to produce firm and fibrous products with a subtle algae odor. It is still unclear how the algae products react to further processing such as freezing.

The researchers also conducted an online survey on food acceptance with Spirulina involving more than 1,000 consumers in Germany, the Netherlands and France. Respondents were able to choose between photos of spirulina-filled noodles, spirulina sushi and a protein-rich snack (jerky) as a vegan alternative to dried meat. The spirulina noodles were especially popular. "This is probably because consumers are generally very familiar with pasta," explains Stephanie Grahl from the "Product Quality of Animal Products" department at the University of Göttingen. Heike Kreutz, bzfe