When you think of the way food tastes, what is the first thing that comes to mind? Perhaps descriptors like: sweet, sour, bitter, salty. These are certainly key elements that affect the way we perceive the flavor of our food. However, there is something else, equally essential yet often overlooked, that affects are opinion of food – mouthfeel. The word refers to the texture and physical feeling you get from what we eat. Ole Mouritsen is a food scientist and the author of Mouthfeel: How Texture Makes Taste. He talked with our contributor Russ Parsons about the importance of mouthfeel, and how he analyzes our response to and physiological interaction with food. Mouritsen also gave us two recipes: Caramelized Potatoes and Vegetables, Prepared So That Children Love Them.
Russ Parsons: When we think about food and cooking, we mainly think about tastes and aromas. But, as you point out in your book, there's an equally important aspect called mouthfeel. What exactly does that mean?
Ole Mouritsen: Mouthfeel is the technical term; we also call it texture. As a technical term, it refers to the sensation of touch and feeling. When most people talk about taste, they don't mean the taste that is technically on the tongue; it's just as much in the nose, ears, or eyes. Also, very much in feeling in the mouth. Usually we don't think about it, unless it's contrary to what we expect. Suppose we get something which is supposed to be crisp and it's soggy, or we get a piece meat and it turns out to be chewy, not tender – then we actually notice it. In most cases, we don't have a word for it. I suppose the word “mouthfeel” is not a common word, but it's important for the entire taste experience.
Ole G. Mouritsen
Photo: Jonas Drotner Mouritsen
RP: In the book you point out that the Japanese have 400 words that describe the texture of food, but we in America have only 80 or so.
OM: That's right.
RP: And the Japanese have three different words for mouthfeel itself. How do you feel this is reflected in their cuisine?
OM: First of all, it reflects that the Japanese are observant as to this particular feature of the food, that it has texture and mouthfeel. It's reflected in the way, for instance, they treat food from the ocean. If you have fish in Japan, you'll see that they pay great attention to the actual texture of the fish. Most fish don't have much taste and flavor, but it's the texture that makes it different from one kind of preparation to the next.
There's one thing in the classical Japanese cuisine which I'm very interested in at the moment, and that's particularly where you treat vegetables. There’s a technique called tsukemono, which basically means “pickle things.” Most of us who have had a Japanese meal see that you have little side dishes; it could be cucumber, eggplant, or daikon. They marinate it, and they have different colors and flavors. Sometimes, if you touch them with your fingers, you think they're not very interesting because they're flexible. But once you get them in the mouth, you have a crunching feeling all over your skull. That shows that the Japanese have extreme attention to the mouthfeel. By the way, when it comes to vegetables, it's a wonderful way of eating more vegetables – that you focus on the crunch.
I'm also quite fascinated by seaweeds. Seaweed is something that is gradually coming into the Western cuisine, but in Asia – Japan in particular – seaweeds are very common. It is something you eat every day, not only as an addition, but because it has interesting texture. It can be chewy, slimy, crunchy, soft, or hard. The different kinds of preparations, for instance, in miso soup or a seaweed salad, reflects a deep attention to the feeling in the mouth. Much less than the actual taste and the aroma, because seaweeds don't have much taste of their own.
by Ole G. Mouritsen and Klavs Styrbæk
RP: You also point out in the book that in a blind test of puréed foods, most people could only identify 30 to 40 percent of them by taste alone. Which foods were easiest – and hardest – for people to recognize? Why is the texture of that food so important?
OM: One of the most successful experiments we do with the public is to prepare a jelly made out of various kinds of cabbages. It's only about 5 percent who correctly recognize it. That usually is a big surprise because you cannot recognize it from the taste alone; you’re actually using feeling in the mouth. With tomatoes, about 50 percent can recognize it. There are all the things like the various kinds of meats you can more easily identify. But it is very difficult if you remove the original mouthfeel.
RP: At the same time, you included an experiment for making ketchup where you used identical ingredients, but you processed them differently. One was perfectly smooth, the other was coarse and chunky. You found that the flavors were remarkably different. How does that work?
OM: It’s not the flavors that are different; it is the mouthfeel that is different. To the extent that you would say the flavor is different is possibly because the release of the aroma compounds may be different when you have to chew and when you don't have to chew. In principle, since it is made of exactly the same things, it has the same taste and aroma. But the way it feels in the mouth, it's very different.
Accepting the mouthfeel is dependent on your expectations and previous experiences. Expectations are also quite dependent on your culture and the way you're brought up. That's what makes the whole perception of taste so exciting. It’s not only physiology; it's just as much your upbringing, culture, tradition, and expectations.
RP: Creaminess, as you point out, seems to be a special case. Technically, it's a texture, but it's one in which all of our senses combine. Can you describe what's going on?
OM: It's something that is not known in detail. One of the important aspects of creaminess is that it has to flow in a certain way in the mouth. For instance, take a mayonnaise. We think that the reason why mayonnaise feels creamy is because oil droplets have to be a particular size, such that they're basically ball bearings in your mouth. It makes it feel smooth. If the droplets of oil are too big, it will feel oily, even though it has the same amount of oil as a proper mayonnaise. It’s a matter of the sizes of the droplets, the way it flows in the mouth, and also the way it clings to the surfaces in the mouth.
RP: There are certain aromas that emphasize the feeling of creaminess – such as vanilla.
OM: Yes, most people know that if you add a vanilla flavor, you feel it's creamier, even though it may not be. It is related to the experience you have earlier that we call it binding. A lot of the talk nowadays about taste is interpreted by processes in the brain. There's even a new field of science called neurogastronomy that reflects on the neuro-processes related to the way you perceive food. Quite often in the brain, we bind different things together. If we have an experience that vanilla and creaminess belong together, then we meet vanilla in another context, we attempt to interpret it in the sense that it's creamy, even though it may be less creamy than it actually is. In this way, previous experiences and expectations frame the way we experience the taste of food.
Russ Parsons is author of How to Pick a Peach.