By changing the color and shape of food it's possible to change its flavor – experimentalist chef

SS: All right, so your culinary experiments lie in the field of what you call gastrophysics, the physics of taste. And we used to think that areas of the tongue detect different tastes but turns out, it's not really the case. So how does our perception of taste work? I mean, how do I know that the berries in my mouth are sweet and coffee is bitter?

JY: Well, flavour is quite a complex construct. So we tend to think of flavour as being made up of two main elements. One is our perception of taste, as you mentioned, so everything on our tongue, so salty, bitter, sour, sweet, and even something called umami, and our sense of smell. And when you put the two together, you get flavour. But actually, from our research, we found that flavour is much more of a multi-sensory and cross-modal perception. So what that means is, it's more about how all of your different senses come together. So not only how things smell, and how they taste, but also how they look and the feel of them and even the sound of them. And all of these very rich, multi-sensory elements, as we are eating and enjoying foods, are all coming together in our minds to construct the expectations, the judgment, the enjoyment or the dislike of the foods that we're eating. And so flavours   a much broader topic than just looking at taste, essentially.

SS: So with taste, we have sweet, sour, salty, bitter, right? When I eat, let's say, strawberry ice cream, if it were completely up to me, I'd only taste sweetness, yet I taste a lot more than that. Where does this ‘more’ come from in my brain?

JY: Well, the ‘more’ will come from, number one, the aroma will play a large role in that. So we all know if you're not feeling well or if you have a cold that maybe your sense of smell doesn't work so well. And when your sense of smell isn't working, we're eating foods, we tend to see the food doesn't have much flavour, it doesn't taste that much. But you can keep adding sugar to your coffee or salt to your steak and it gets sweeter or saltier. But that doesn't improve the flavour in any way. So a sense of smell is vital for when you're eating something like as you said, strawberry ice cream. Strawberry is made up of much more than just sweetness. There's a lot of other molecules and compounds there that are contributing towards flavour and that distinguish let's say strawberry from raspberry or from blackberries. And that's a vital element of us being able to kind of really make a distinction between a strawberry ice cream and a raspberry ice cream. If you didn't have your sense of smell, or if you clipped your nose as you were eating them both, they probably both taste pretty much the same, they'd be kind of sweet and maybe a bit sour in some way, but essentially, it’d be very difficult to tell the difference. Now with something like ice cream, the other element is obviously the mouthfeel and the texture and the creaminess and all of these elements are what are coming together in your brain to give you – and the temperature, let's say, of the ice cream as well, – so all of these are things that your brain is taking into consideration when it's trying the ice cream and that it's making judgments based upon. So if you have an ice cream, and it's very icy or it has a kind of crunchy-ish kind of texture, where it's kind of very frozen, that might not be as pleasant as when the ice cream is nice and soft and smooth in your mouth and melts really well. So it's not just about the sweetness or the sourness or the bitterness. It's also about all the other factors that are going on that make ice cream so enjoyable for us.

SS: So if I got your idea right, food flavour is a brain construct, rather than a sensory perception in our mouth. So are you saying basically that if I convince myself somehow that lemons are sweet, they will taste sweet?

JY: No, because there's the important thing with flavours, you've got kind of two elements working here. One is your chemical senses so your sense of smell and taste and these are reacting to the chemicals in the foods and giving you a certain perception. But then you have the other elements, as I said, like things like texture or sound or the visual of it. So if you were eating a strawberry ice cream, but it was blue colour, well, your brain isn't going to register it as being strawberry initially. So maybe when you try it, you will disconfirm, maybe if you see the ice cream is blue, you might, let's say, for example, think it's blueberry and then when you go to eat it and it turns out that it tastes of strawberry, well, then your brain would be very confused by that. And so what would be better in a situation like that is if we want you to register it as being strawberry ice cream is that we make it as red as we can, or as close to strawberry colour as we can for your brain to be able to really kind of confirm its expectations. But no, it's not enough. You know, you can change certain attributes in one sense, and that can confuse the other senses or can maybe direct them towards making a slightly different judgment. But you can't convince your brain that eating strawberry ice cream is a different flavour because there's too many physical parts of it that when it comes to your chemical sensors that can't be fooled in such a simplistic way.

SS: I still wonder like, how far can we manipulate our brain? Let's say, maybe I can't convince myself but can other people convince me if they know in detail how flavour building works, I mean, can senses which produce the experience with flavour in our minds be manipulated and create a convincing illusion of flavour? No?

JY: Yeah, so there are certain things you can do with food that will in some way augment – so as I said, maybe changing the colour of the food can change your perception. We know a lot of people if they're eating something like a green jelly, if you present them with something like, that's kind of like a jelly and it's a green colour, that a lot of the time, they'll assume that the flavour is either something like lime or apple. And even if you flavour it with something different, a lot of the time people find it difficult to kind of distinguish or identify what it is because the sensory cues aren't quite right. And you can in some ways, even through things like sound, make foods taste crunchier or fresher than they are. And when it comes to texture, you can also augment flavours so that you can kind of trick the brain slightly. But at the same time, it is very difficult to convince your palate that you're eating one flavour versus another. But there are little kind of sensory things that you can do. Kind of what we do with the researchers looking at how you can make these little sensory changes within the food encourage people towards making maybe more sustainable or nutritious or healthier food choices. And this is specifically looking at with like kids or hospitals or care homes, and looking at how we can design food experiences to encourage people to make better food choices.

SS: Well, culinary artists, chefs like you, approach eating not as just food consumption, but it's like a multi-sensory experience. And you mentioned smell. Let's talk about that. When there is a big   of soup, obviously the smell fills the room. But when I eat, let's say, a potato crisp I maybe only smell it for a second before eating it. How do I smell food that is already inside my mouth, past my nostrils? Shouldn’t I lose the flavour the minute I consume food?

JY: No, you have two senses of smell. One is called orthonasal, which is, as you said, the bowl of soup and it's in the room and everything that you can kind of smell around you in the environment and as you're lifting the spoon up to your nose, you can smell that kind of aroma of the soup. All of that is what you would call orthonasal. And then once you put the soup into your mouth or whatever the food is, then you have something called retronasal smell, which is all the every time you swallow, there are little bursts of air go up through the back of your olfactory system, which is what makes up your sense of smell. And that gives you a second perception of aroma. So this is why as well, you can smell something like quite a smelly cheese that maybe doesn't smell so great and it's quite pungent, if you think of a kind of unripe French Brie or something like that that's quite pungent and smell. But once you put it in your mouth, it tastes delicious and the flavour is great. And it doesn't smell the same inside as it does on the outside. And that's because you're chewing it. It's mixing with your saliva and it's undergoing a certain amount of processing as well. That is changing that aroma construct in some ways. So what's important to understand is that, you know, the two senses of smell are very distinct and work in slightly different ways. But essentially, even when you put the food in your mouth, you are still smelling it only with a difference, not necessarily directly through the nose.

SS: You know, I think it was like a decade ago, Cadbury updated their dairy milk chocolate bars, and there was like a modest uproar that ensued and people were claiming that it has become sweeter and then food experts, chocolatiers were weighing in. And then it turned out that the recipe hadn't changed a bit. And they just made the edges a bit more round, which somehow made people sure that the taste had changed as well. So, here our sense of flavour is informed by the shape of this sweet I’m eating by my sense of vision?

JY: Yeah, I mean, there's all sorts of interesting associations that we have, and expectations and judgments that are set through our eyes. I mean, there's in experimental psychology, this notion of visual dominance. So what we see with our eyes sets judgments and expectations. And a very kind of simple example I could show you of that would be if I was showing you these two shapes. And if I was to ask you which of these you would call Booba and which you would call Kiki. So Booba and Kiki, if I say,d this one would be –? 

SS: That will be Kiki and the other one will be Booba. 

JY: Yeah, and about 98% of the world's population will go with that kind of correlation. There's no right or wrong answer for it. But what's interesting is that we found that even if you talk about food and flavours, so if you talk about sweet, creamy, fancy, chewy, soft, comfort food flavours, most people will associate those with Booba. If you're talking about tart, acidic, crispy, crunchy, sour kind of flavours, or spicy flavors, most people are associated with something like this shape over here – Kiki. And what's interesting about that is that although there is no right or wrong answer that the majority of people have that kind of association. So when we see foods that are maybe red, or orange, or yellow, maybe we assume that they're going to be on the sweeter side of things. If we see foods that are rounder and softer looking, maybe we assume again, that they're going to be sweeter in some way versus if we see foods and other kind of colors or shapes. So there's all sorts of things that you can get. So in the Cadbury's example, that you just gave with the chocolate bar, there could be two reasons behind why people felt it was sweeter. Number one, the shape was rounder of the bar. So maybe that means it melts differently on the tongue, maybe there's more surface area, and maybe that's why people got a bit more sweetness out of it. Then the second reason is maybe just because it looked rounder that people assumed from the visual presentation of the chocolate that in some way, it was sweeter.

SS: And then there is a correlation of colour and taste. And you talked about it quite a bit as well. We generally associate white with salty, black, brown with bitter, green with sour, red – sweet. Where do these associations come from? I mean, why, for example, we associate white with salt if sugar is also white?

JY: Yeah, no, I completely agree. And there is no, you know, research, if anything has identified that we have these associations, it hasn't really specified why we have these associations. And one of the reason being is that, you know, this can change from even region to region. When, say. the majority of people around the world when we did that research, so about 70-75% of the world's population will say white is salty, black is bitter, green is sour, and red is sweet. But then when you go into different parts of the world, so when we went to Sweden, for example, most people said black was salty because they were associating it with salty liquorice, when we went to Asia, in some parts, they said, black was salty, because they were associating it with things like soy sauce or fish sauce. So there will be regional and kind of cultural differences that play into this in some way. But what's interesting is that the majority of people when put into that kind of forced choice of making an association between a color and a taste, will kind of agree on what that is. And that could be maybe out of that choice. Salt is white. So we go with kind of white being salty, blackish brown, you think maybe it's things like tea and coffee, maybe it's, you know, burnt charred foods have a kind of slight bitterness to them. Green being sour, maybe because of sour candy or limes. There's even a hypothesis that it could be a more innate part of our brain that thinks of unripe fruits being kind of green and sour, and ripe fruits being sweet and juicy and ready to eat. So we don't know exactly why there are these correlations exist, but what we do know is that they exist. And that's very interesting, because then if you come to the design of food, or the design of food experiences, understanding those kinds of correlations can maybe help you with designing foods or food experiences that encourage people to make better food choices.

SS: You know, we love foods that also look more weird than tasty like oysters, I’m thinking, or durian, I mean that Asian fruit that smells like hell but when you taste it it's really good. So for certain foods, do we switch off certain senses like visual sense or a sense of smell when it comes to enjoying them, or does it always come in a package?

JY: No, all the senses are constantly working a way like apps in your phone in the background. When you're eating your sense of hearing doesn't kind of shut down, everything is constantly always ticking away in the background. So it's maybe if you become more aware of it, and this is a big part of what we do with the dining experiences at our Chef's Table is encourage people to be more mindful of their senses as they're eating. So in the case of something like durian, which you mentioned, you're right, it does smell pretty bad when you first cut the fruit open and you're smelling it, as we said, orthonasally from the outside. But once you bite into it, well, then the retronasal side of things kicks in, and all of a sudden, it becomes something that we kind of enjoy in some way. But, you know, it's important to understand that if all your senses are functioning normally then they're constantly kind of working in the background and feeding your brain with this very kind of rich information. And if you don't like how oysters look, then chances are it's going to be very hard unless you change the way the oyster looks, unless you've manipulated it in some way, even by deep frying, or doing something like that, just by changing the visual, aesthetic and presentation of it, even that may be enough to encourage someone to eat it or enjoy it. But generally, all the senses are constantly working. And what's most important is that they're working together. For people to have a really enjoyable multi-sensory food experience, being mindful is probably one of the most important parts of it. Because, you know, as we always say to people, you can eat a sandwich sitting, you know, on a train between meetings, kind of rushing from one place to the other. And it's not going to taste as good as the same sandwich if you would sit on a nice park bench on a sunny day, like the nice sunny day that you have behind you there, enjoying it in nature and kind of taking in the texture and the flavour and the aesthetics of the sandwich. So our senses are constantly working, but we don't always focus them on what we're doing. And a big part of what we do at Kitchen Theory with multi-sensory dining is making sure that people really are aware and focused and mindful of each of their senses as they're enjoying their meal.

SS: Can there be a taste experience that is pure, not enhanced by music, light, shapes, colours, etc.? Would that taste experience be more true to others? Will I know how chicken really tastes if I eat it without, let's say, looking at it at all?

JY: It may do. But then again, you know, if you're talking about something like dining in the dark, where you don't get to see your food, most people find that quite novel and interesting, but in the long term we don't really necessarily enjoy not being able to see our foods. I think you only have to take a look at Instagram to see how much people enjoy culinary voyeurism and looking at food, and the whole idea of food pornography and all the content that's uploaded around food... We enjoy as human beings looking at food, and it kind of opens our appetite, it makes us want to engage with it or not want to engage with it. And as for, you know, the other senses, if you were to strip it back, and you have if you think about it in, I guess the late 80s, early 90s, a lot of restaurants were going for much more of a kind of almost art gallery style: white walls, white tablecloths, very strict, very simplistic. And it was all about the food that was on the plate. And I think now we're starting to understand more and more, people like seeing the open kitchen, people like the showmanship, they like the music to be congruent and fitting with the atmosphere and mood they're in, they like the texture of the chairs and the tables. And all of these things are important to our experience. Whether we're registering them mindfully or not, is one thing. But this is all information that's kind of being fed back to us. And I think for us to really be able to enjoy food, sitting in a blank room, with a blank table with a piece of chicken in front of us is not going to be anywhere near as enjoyable as enjoying that same piece of chicken in the company of good friends in a nice environment. And that's the kind of elements that really come together to give us– You know, dining is also a very social thing. And it's a very, you know, sensory and social activity that we enjoy taking part in as part of a community or as part of a group. So I don't think dining in isolation really gives you a purer version of eating. This is why we do a lot of tests in the lab, but we also try and take these ideas from out of the lab and put them into the dining room, because people tasting foods in a lab in very sterile conditions isn't necessarily how we taste things in the real world. And so there's a big difference between the two.

SS: I know that your mission, in general, is using your knowledge about food as a multi-sensory experience and then by that inspire people to eat better, to eat healthier. So I understand, for instance, that the colour of a plate can make chicken breasts and broccoli on it look more appealing. But what are the tricks that you could use to make people eat less sugar or salt?

JY: Well, maybe augmenting – so that we talked a little bit about kind of like shapes and texture – so if I was designing, let's say, a children's dessert of some kind, maybe you want to make sure that the packaging that it comes in is really red. Because we said red is the colour of sweetness, so reds and pinks and oranges and colours like that that really scream sweetness. Maybe we want to make sure of the colour of the product, the yoghurt or ice cream itself, let's say is a deep tone of red, that kind of tells the brain that there's that sweetness there that we're craving, then there's the shape of the packaging, maybe you'd want to go for in the case of sweetness, you're going to make it rounder in some way and more soft and maybe the texture even of the material that the packaging is made of. We know that people if they're holding something like velvet, or silk or something smooth in hand that they'll find food sweeter and creamier and smoother than if they're holding something rough in hand like sandpaper or a rough piece of velcro. So thinking even about the design of the packaging, think of the design of the ice cream or the yoghurt itself in terms of its texture, and its creaminess and smoothness. Now, that's not to say that you can take out all the sugar from this food or dessert and simply replace it with these other sensory elements. However, what we're saying is even if you can make small reductions in the amount of sugar that you put by augmenting the colour, by changing the shape, or the texture, or even what people are listening to as they're eating it, all of these elements can combine together towards allowing us to make small reductions in things like salt and sugar across the board. And obviously, these small reductions can over time add up to something more important.

SS: You know, it's funny, I've noticed that as I move through life natural becomes tastier to me. You know, like teenagers can drink gallons of Coca Cola but adult people around me stick to sparkling water or flat water with lemon. And it's not just a question of cellulite, or you know, chemicals in the coke. It's just like it tastes better because it tastes simpler. Does love for chemically enhanced food, wither with age? And in what other ways age affects perceptions of taste?

JY: So it's not so much about chemicals, as much as about what you just mentioned there, which is age. So when you're a baby, obviously you nutritionally crave completely different things than when you're a teenager, than when you're adult and when you're elderly, you know, getting older in life. Even things like texture of food will change. When you're a baby you simply don't want solid foods, and on the opposite end of the spectrum, and then when you're a teenager, let's say, you love crunchy, crispy, crackly food, even into adulthood. But then as you get older, maybe again, softer foods become more palatable and more enjoyable again. So there's both a kind of physical requirements of food that will change as we kind of grow and age. And then there'll be the nutritional requirements that we have. We can see this in, let's say, women who are pregnant, that they'll have different nutritional requirements or people who live in different parts of the world, or have different jobs that they'll have different nutritional requirements. So it will change very much from one individual to another. But what's for sure is that our palates and what satiates us and what we enjoy definitely changes over time. And one of the reasons would be for something like soda when you mentioned there as well is, as we get older, maybe we become more aware of the ramifications or the cost of drinking so much sugary, sweet carbonated stuff. My point is that as we get older and start to maybe change our priorities (when I'm a teenager, do I really care as much about my body shape and weight?), well, maybe that's where I'm starting to become more aware of it and maybe into adulthood, I start realising that, well, actually, the taste of that coke as good as it is doesn't appeal to me quite as much because I have different priorities in what I find tasty now or how I classify good flavour or tasty foods.

SS: Thank you so much for this wonderful insight into the world of food, taste, palates of our taste. It's been really quite interesting talking to you. Thank you so much.

JY: You're more than welcome.

SS: You've emphasised that this is a whole new science and it's not just food. I wish you all the best of luck and I hope we can do this in person once.

JY: Most definitely. I look forward to it.

SS: Thank you so much. Take care.

JY: Thank you. Have a great day.