Per Møller

Per Møller

Professor at the Department of Food Science at the University of Copenhagen

If we could trust flavor as a guide to a healthy diet, the world would be a happier place, and probably without the endless fight between Atkinson and Zone diet fans. Unfortunately things aren’t that easy. Our taste for food depends on a complex combination of factors such as appearance, texture, odour, pungency, and on our “breast-fed infant through to early childhood” times, when we were basically forming the basis for our food habits without being aware of it. Famous for being one of the initiators and major contributors to the field of Molecular Gastronomy, Per Møller, Professor at the University of Copenhagen, where he directs a Master’s-level course on Food Choice and Acceptance, and editor in chief of Flavor Magazine, a multi-disciplinary journal that focuses on all aspects of flavour, analyzes our senses, food sensation, reward and appetite under a holistic approach that includes psychophysics, neurophysiology, neuropsychology, neuroeconomics. At Falling Walls he provides a unique chance to understand what our relationship with food is based on, how memory of odours and flavours are connected to specific critical periods of our growth, and what triggers choice and consumption.

Breaking the Wall of Bad Taste. How Psychophysics and Neurophysiology Can Improve our Food Choices


Thank you. I guess it is appropriate that I speak about taste just before lunch. If you happen to dislike the lunch, I hope to demonstrate to you that there is still hope. Because, breaking the wall of bad taste, or rather, I think opening up the wall to almost any taste is indeed possible. I will show you some examples of that and explain some of the mechanisms. But, when we are talking about tastes, we better sort of discuss what we mean by it. And, you all know that we have five, so-called, basic tastes: sweetness; you are familiar with sweetness, saltiness, sourness, bitterness, and then this other, so-called fifth basic sense, umami. I think that you will have a taste of a typical umami thing now, right? (So, if you pass these things around.) Umami is a savoury taste associated with monosodium glutamate and small peptides. It is meaty and savoury. It has been found that in order to explain all of what the tongue can do with taste, we need to include other tastes than the four usual ones. But, this is not taste on the tongue. What I am talking about is really taste of foods. When you have a cold, which I am sure that you have had, your food has not tasted the way that it should. That is really, because taste of food is not taste in the taste sensation from the tongue sense. Taste of food is really a highly complicated interaction between taste sensation from the tongue, smell from the nose, touch or tactile sensation—so-called mouth feel; you can tell the difference between a chewy thing and a non-chewy thing. Then also, what we call trigeminality, or chemesthesis, which allows you to perceive hot spices. When all of this come together in the brain, as this highly complicated figure on the left illustrates. We refer to it as flavour, and flavour, in a scientific sense, is really what we mean by the taste of the food we eat. So, what we need to understand is flavour perception, or maybe, rather than understanding flavour perception, we need to understand flavour appreciation. We heard about perception and attention just ten minutes ago, and that is also very important here. But, two of us can have the exact same percept of a thing. For example, this cube is red to me, and I am sure it is to you also Stefan, but you might like it much more than I do, right? So, appreciation does not follow immediately from perception. And, if we deal with how to change what we eat, either to get more pleasure or to be more healthy—less obese—we have to understand where preferences come from. They could be coded in our genome, and it seems as if three of them are: sweetness, the appreciation of sweetness, and the appreciation of fattiness as well as a dislike of bitter taste.

This is very, very clever of nature to have put it together like that, because if you think about what we eat from the first six months of our lives, it is mother’s milk, right? Mother’s milk is sweet, and it is fat. So, if you have an inborn acceptance mechanism or preference for sweet and fatty foods, you might pass the problem of hard communication, verbally speaking, with the baby. Also, the dislike of bitter is highly appropriate, since in nature very many poisonous plants actually taste bitter. But, except for these three examples, all the rest of it is learned. Which means that, incidental learning—and by “incidental” I mean non-intentional learning—becomes important to understand if we want to change what we should eat—either for health reasons or because we have other concerns. And there are a number of mechanisms for preference change, and I will show you some examples of all of them with real data. But mere exposure is also known in many other fields, but in sort of the food information, food preference information field, it means that just exposing an organism to a stimulus a sufficient number of times will have the organism appreciate that particular stimulus more —nifty mechanism. Conditioned learning is well known to some of you, but if it is not, I will explain what it means. If you have a stimulus that you unconditionally like and you pair it with another unknown one that you do not like, at the beginning, if you pair them into a mixture and have a human or an animal eat or consume this, then after say 10 exposures to the mixture, if you take away the originally unconditionally liked stimulus, the organism will like the new stimulus more. So, it as if the nice properties of the unconditional stimulus has been taken over by the initially not-liked stimulus. Of course that is not the case, but it is as if. So, the brain has been recoded. It responds differently to the exposure with the unknown, in this case, food. Instead of using a well-liked flavour, you can also do this trick with energy. So, if you add fat to an unknown food or unknown flavour and have the organism or person eat it, eventually the energy will do the trick; because after the eating, you will feel energised, and that will, in a mysterious ways, change your approach to the new flavour. That is called flavour-nutrient learning. And there are other mechanisms, but I would rather show you some examples of how this works and when it actually starts.

In the first slide here, it is a very simple and extremely nice experiment performed by Benoist Schaal and his colleagues in France. What they did was the following. They got two groups of pregnant women. Two weeks before they were to give birth, they offered the same meals to the two groups with only one exception: one of the groups had a little bit of anis added to their foods. They ate it; it is very common in France to add anis to their foods. They were very happy about it, and they gave birth to their children. Now, the test was performed on children, or newborn babies, one to eight hours after birth—very early. And, you see on the left panel what they did: they took anis odour on a cotton stick and put it next to the nose of the baby. Babies born from mothers who had consumed anis had approach-behaviour towards anis. Whereas those born to non-anis eating mothers, repulsed—moved away from it. So, it seems that already in the foetal state, what we are exposed to in terms of flavour chemicals affects our approach-behaviour, or our liking of flavours. This continues into the lactation phase. The first-half year of the child’s life, he or she lives from mother’s milk. In the plot, we have shown that flavour chemicals are transferred into the milk, and that can be quantified, and we can measure delays. If you do these experiments with women—say that was menthol there—if you have a group of women who lactate children with menthol in the milk and another group of women who do not have this menthol, then exactly like in the foetal case, children will have a higher preference for menthol in foods if the mother’s had this in the milk. When we get older, in this case this is data on two- to three-year-olds, a completely unfamiliar, unknown, food, and in this case it was artichoke puree, which is not eaten very much in Copenhagen, to these children; artichoke puree was really unknown, and they were unfamiliar to it. You see, at the very first exposure, they managed to eat 20 grams of it, which is nothing—it is just what they spill on the floor. But after 5 to 10 exposures, they would happily eat this up to 120 grams. So, this demonstrates that learning, incidental learning, takes place not only in the foetal state, or in the lactating, but also after we have started to eat solid foods.

Food control mechanisms used to be food control mechanism, so-called homeostatic mechanisms, but it has been realized now that hedonic mechanisms are also very important. So, there is a lot of research in neuroscience and psychology going into understanding what is reward. That is good, because we are faced with a challenge—if not only by sustainability concerns—they would seem to imply that we need to dramatically change the foods we eat. As I hope this data has suggested that there is more to be read about in the literature, if you are interested, it is certainly possible. It is a bit unfortunate that I don’t really have time to share with you these nice examples of highly unconventional foods. This is stuff that you usually find on the beach: seaweed. But, it can be turned into very nice foods, as Ole Mouritsen, a physicist in Denmark and a highly inventive cook has demonstrated here, or something that is a bit like what you ate before, and it can be used to flavour all sorts of products. They get much better than without them; so we get stuff from the very bottom of the pyramid. We don’t have to have it all pass through. Thank you.