Max Planck Institute: Replicating foie grass texture and flavor to reduce force-feeding concerns
15 Apr 2025 | Max Planck Institute for Polymer Research
A team of researchers at the Max Planck Institute for Polymer Research in Germany has developed a process to manufacture foie gras, a delicacy often associated with concerns over force-feeding of ducks to increase liver fat deposits. Author Thomas A Vilgis explains the challenge of replicating the dish’s unique texture and flavor, and how the scientists overcame them by using lipase enzymes.
Hi, this is Inha Noreen, a journalist at Food Ingredients First.
A team of researchers at Max Planck Institute for Polymer Research in Germany and the University of Southern Denmark has developed a method to recreate foie gras, which is a delicacy often associated with concerns over force feeding of ducks.
We are joined today by Dr.
Thomas A.
Wilge to tell us more about the innovation and its application.
So my first question is, what inspired you to embark on this project of creating an alternative to foie gras?
Yeah, I came across, foie gras in France because I worked for 2, for, for 2 years in France, and then you can't avoid it because you go to restaurants and you see these things and then I saw it the first time there and, and, , I liked it because it has an exceptional mouthfeel, it has an exceptional texture, it has an exceptional flavor release.
So, , I started to like it and so, but there is always in the background that there is, this force feeding and it is not.
Not really animal welfare, but somehow, of course, there are farmers who do it in a soft way which is less cruel as an industrial basis.
But nevertheless, there was the challenge, how can we get this kind of exceptional mouthfeel, texture and flavor release by just using the basic ingredients which we know from foie gras because foie gras consists of liver.
And fat, the fat is coming from the force feeding, the, the, the, the swelling of the liver as and , and so there was the challenge, how can we recreate that given that livers exist and also duck or goose fat exists because when these animals are slaughtered, you can buy these ingredients anyway.
And is there, is there a method just to use this tool?
Ingredients which are not stemming from force feeding just to recreate a kind of worker, that was the issue.
OK, that's very interesting.
And how do you ensure that the texture and melt in the mouth experience that you talked about, mimics really the traditional foie gras?
It is, it was a real challenge because first of all, we tried to just mix it, right?
We just tried to, to, to, to mix liver and, and, and, fat, duck fat in the, in the, in the, in the right proportion how it exists in the foie car and then we got a sort of liver sausage, but it was far away from, from, from the, from the foie gras.
The, the taste was OK.
The taste we can manage, but, but the mouth feel was not good.
The, the, the, the flavor release was completely different, and the melting properties in the mouth have been also very different.
So we just tried different issues like, adding collagen and, and adding diff different emulsifiers which we know from, from, from, from meat technology, but we never could reach this really exceptional mouthfeel.
So there was something missing in our, in, in our imagin way of thinking.
And the, the crucial point was indeed because at that time, I met also, , , Matthias Posmosse Clausen from, from the Institute of the, of South Denmark.
And, , then he came across with this very beautiful method of, of cast microscopy where you can just look at the fat structure without destroying the whole thing.
So it was a non-invasive, way of, of making microscopy of, of, of the fat structure and then we saw the difference because the difference in what grava large fat clusters.
And these large fat clusters, they had They are responsible for a different sort of mouth field, different texture because it's a particle network or something like that.
I don't want to go too much into these details, but, , we saw immediately what, what makes the difference.
And the question was really, how can we achieve this kind of fat structure inside our product?
And then, I remembered just what is the duck doing because when it's, when it's fat, it has to digest the food.
And when it digests the food, it, it uses enzymes.
And, and one of the most important enzymes, apart from proteases and And, and, and, and, and amylases and things like that, but it's lip lipase because the lipase acts on the fat.
And so we just tried to, to treat our fat, our usual normal duck fat with this lipase and then we saw there's a restructuring of the, of the fat structure.
And then there's a restructuring.
Of the fat and we could prove it with different, different methods.
X-rays, we looked at, and, and, and, of course, at the, the, the, the, the color, color calometric methods just to, to get the, the melting points right.
And then we just mixed the fattens , it, it was, from the beginning, the first trial was already Far away from the, from the things we did before and it was already very, very close to the, to the forecast and then we continued to make the fine tuning.
OK, great.
Thank you for explaining that so clearly for us.
And how do you think the nutritional value of this product compares to the conventional foie gras?
It's the nutritional values are almost the same.
It's, it is, it is even a little bit better because on average, the, the, the, , traditional foie gras with force feeding, they have a little bit more contents of saturated fatty acids, but this is not a really dangerous.
Dangerous, but because it, it, it's fatty anyway.
Both products are fatty anyway, but, but, but it, it, it has a little bit of advantage but it is, the crucial point is that the fat structure which comes out of the, of the usual duck fat which is subcutaneous fat or some, or, or the usual duck fat which you can buy in the butcher's, butcher's places, that this gives already the good fat structure when we treat it with the lipase.
So the nutritional values are about very, very similar, I would say.
OK, great.
Thank you.
And how do you think that your alternative product is, has the potential to influence the broader food industry, especially when there are a lot of concerns about sustainability and ethical production?
What are your views on that?
It's, it's a difficult question because, , we cannot avoid slaughtering because that's, that's, we, we need the, the ingredients, but there are people who slaughter and, and, and, we can use these products.
This is the 1st, 1st, 1st point, so it's not really a, , , a really clean product because still animals have to be killed.
The other thing is, , we will never avoid.
Perhaps the, the traditional force feeding in countries where it's, where it's has high culture like in France, for example.
That's, it's also, we are aware of that because there will be always a sort of tradition which, which will kept, which be a culture which will, which will kept alive.
But on the other hand, there are many demands on foie grasing restaurants and In, in, in, in, in many places, , and often we find crucial methods, , or, or, or cruel methods, better to say, where really ducks are not living in the, in the, in, in, in freedom because they are kept in cages.
They are force fed from a certain age on, so it's a really sort of very, very speedy growing, the, the, the, the, the, the animals which have never seen daylight and things like that.
This is sort of industrial force feeding.
And perhaps we could jump into this kind of, of really cruel behavior, cruel treatment of the animals that our method gives at least an alternative to go beyond such things and have a similar kind of product.
I think that would be already sort of , , gained in the, in all these ethics, but of course, we have to slaughter in this, in, in our, for our products.
Yes, indeed.
And in future, what potential do you think your process has?
And do you think it can be used by large food manufacturers or in the restaurants?
Yeah, I think so.
It's, it's because it's very simple.
It's really, it's, it's really perfect for, for industrial production because of course, we, we, we just did the lab, lab size, so, so we, we just had small sort of portions but it, it is a process which can be upscaled.
It's perfectly for, for, for, for large but butcher factories or, or meat factories who can treat, because we have to cut the meat, we have to, to emulsify with usual cutters which, which, which are anyway there in the, in, in, in, in the, in the meat production for, for sausages and for other things.
So, so it, it's perfect for the, for, for them because the, the, the lipase treatment is not so, not really so complicated and it can be done in, in, in sort of Demand, it can be done also by, by the fat can be stored.
There's no problem.
We stored it also for some time and so you can put it together and this is not a real, a real problem.
So I think there is much potential to make a sort of foie gras which is, which is not force fed coming from classical ingredients.
By the way, this works also for, for, for, for pork fat, for, for pork livers.
It works also for, for chicken and chicken livers, chicken fat.
And chicken livers.
So there are many ways now to improve, let's say, products but are like but coming also from from, from other animals.
So there is a lot of potential which, which, which is hidden in, in, inside this sort of universal, , , treatment.
But that sounds really interesting.
I think if you are also able to apply it to other products that could really change something for the food industry.
And coming to that, do you have any upcoming collaborations or maybe some feedback from food manufacturers?
No, , so far not, but, we, we are open to, to, to, to, to cooperate and, , this, this work has been patented, so, so there is, there is a way how to, there's a clear way how to cooperate and so we hope that let's say on a, on a, within, within, within quite some reasonable time, we, we, we find somebody who tries that, who takes this idea up and just to see how it works.
