Professor Wagemans, meat products made from peas or soy are now established on the market, even major fast food chains offer them. Why do we still need research in this area?
You are right that there has been major progress here. However, we still need to get more people to switch to substitute products if we are going to significantly reduce animal suffering and protect the climate. And biting into a steak remains a unique experience.
Can you explain to me in scientific terms exactly what happens when we do this?
What makes meat special is that it produces many different sensory experiences on different scales. At the macro level, up to about one millimeter, an entrecôte is initially quite unstructured. When you then bite into it and chew, you get to the meso level, where the individual muscle fibers are. You then have structures of a few hundred micrometers. Due to the connective tissue and fat that are also present, however, this is still relatively soft matter. Below 100 micrometers, however, you have to chew well because the myofibrils have a high tensile strength and stability.
So in other words you experience very different sensory impressions in your mouth. Can a pea steak match this?
That’s the question. The big difference is that substitute products are already relatively strongly structured at the macro level as a result of how they are produced.
What different methods are used when producing meat substitute products?
The most advanced substitutes are purely plant-based raw materials such as peas, wheat or soy. Products made by microorganisms or from cultured animal cells are still at the research stage. For the latter, a support structure is necessary so that the cells can attach themselves along predetermined directions to achieve the necessary structuring. However, we are not only working directly on the fundamentals of structure formation, but are also concerned with the technological processes for production. The focus here is on extrusion, in which the raw materials are passed through worm gears, mixed and kneaded to give them a fibrous structure.
Are you also working together with companies that produce meat substitute products?
Yes, we are. After all, we can't conduct research in a vacuum. For example, we work together with Veganz in Ludwigsfelde, a company that sells and produces vegan foods; our projects include vegan salmon and soy medallions. We also have a cooperation with "Project Eaden," a Berlin-based start-up that has just raised over ten million euros from investors. Both companies use purely plant-based raw materials. We also work with a number of companies as part of projects funded by the German Federal Ministry of Economics and Climate Protection, including one in Lübeck that cultivates fish cells and one in Israel that works on cultured meat.
Is it possible to express the sensual impressions we have just been talking about in precisely measurable parameters and then use these as specifications for production?
No; and this is precisely the problem. Today, we still have to carry out sensory tests with subjects in order to be able to assess the final result. But we are, of course, continuously refining our measurement methods; we create texture profiles and measure hardness and springiness, among other things.
What do you mean by springiness?
Something like elasticity. To measure it, we press twice on the food with a stamp and record the force-displacement curve. We can then deduce how it expands again after compression.
It sounds strange when something as fundamental as our food is suddenly subjected to rigorous scientific criteria...
But that's what's so exciting! Food is so complex and comes in so many different forms. There are foams, suspensions, solids, gels, and many other forms besides. And while proteins play the main role in meat, we also often have polysaccharides from the plant source materials in the substitute products. Proteins and polysaccharides, however, are often incompatible with each other in structure formation. To investigate this precisely, we use a measuring device that is only available in three laboratories worldwide.
You mean because it is so expensive?
No, not at all. The principle is quite simple. It consists of two chambers separated by a membrane. In one chamber there is a solution with a mixture of, for example, protein and polysaccharide molecules. On the other side there is only the solvent. As the mixture diffuses there through the membrane, a so-called osmotic pressure is created in this chamber, which can be measured by a pressure transducer. From the measurement curve obtained, we can infer the interactions of the protein and polysaccharide molecules with each other to obtain valuable information for structure formation during production. Unfortunately, this device is no longer manufactured. One of my dreams is to manufacture it in small series with instrument makers.
Well, you should be able to find people at TU Berlin who can do that.
I have no doubt about that, but unfortunately I haven't talked to the right people yet. So, I would be very happy to hear from anyone reading this who can help!
You have already been awarded the Berliner Wissenschaftspreis. How important is that for you?
Very, very important indeed. And I am not just saying that. Science is extremely competitive, you have to hold your own. It's not always easy not to pass on the immense pressure to your own team. People who have children in particular really need a lot of staying power. This award shows me that it has all been worth the effort. After all, I could have pursued other paths in life than science.
I was - and still am - a singer-songwriter. So my scientific career was not always preordained. I also initially went to a very normal secondary school before switching to a technical high school in Schwäbisch Gemünd. At that time, no one would have thought that I would become a professor. While I was still a doctoral student, I even applied to be on "The Voice of Germany," but wasn't accepted. Shortly afterwards, however, a scientific paper I wrote was accepted for publication. That's when I knew I was on the right track (laughs).
Interviewer: Wolfgang Richter