Product development • When you are trying out ‘new flavours’, develop a new recipe or improving an existing one, the taste naturally comes to mind. Especially when sugar is to be reduced or replaced. But the taste is just one component of the food experience. If we want to take a holistic view of the total experience, we must address the mouthfeel. But what is it? And why is it important?
The easiest way to explain mouthfeel is to explain what it is not. Simply put, mouthfeel is the overall experience of food or drink in the mouth – minus the taste and aroma. The term is often used by sommeliers, who talk about how wine is feeling in the mouth, but everyone who works with ‘taste’ should use the term; the taste is just part of the overall experience. In order to take a holistic view of the dining experience, it is important to work with the whole mouth feeling.
Taste and aroma
Our experience of food and drink is composed of taste, aroma, and mouthfeel. It is easier to understand mouthfeel and its significance if you first understand what distinguishes taste and aroma.
Taste is the experience that comes from the receptors on the tongue. These are the four basic tastes: sweet, salty, sour, bitter. Recently, umami has been recognized as the fifth basic taste, as researchers have succeeded in showing that we have taste receptors that recognize umami.
Aroma is really the same as smell. We have about a thousand different smell receptors that have the ability to recognize different types of odorants. When we eat, fragrances are released that enter the nose and reach the smell receptors. This can happen in the duct that connects the oral cavity and nasal cavity (retronasaly), or from the mouth and nose.
Now we come to the mouthfeel. Initially, I wrote that it is the overall food experience minus the taste and aroma. That is largely true, but I will now explain mouthfeel in more depth.
We are equipped with taste receptors and smell receptors, but there is a third element, that is often overlooked when it comes to food. That is the somatosensory system. Simply put, it is our ability to feel. The somatosensory system is found throughout the body but is particularly sensitive in the mouth.
Mouthfeel is part of the somatosensory system. The system senses the physical experiences of pressure, vibration, friction, and temperature differences. Receptors in the tongue, teeth and other parts of the mouth help create the overall mouthfeel.
Mouthfeel is something that the consumer rarely talks about – at least not explicitly. But at second thought, we realize that when something does not really ‘taste’ as it should, it often regards mouthfeel. Chips that have become soft, pasta that has been overcooked, or iceberg lettuce that has lost freshness and crispiness.
The phases of mouthfeel
Mouthfeel becomes more understandable and relatable if we divide it into different phases:
The tactile phase:
First comes the tactile phase. It is the immediate feeling of touch in the mouth. Imagine a fork with meat, sauce, and rice – perhaps a chicken stew. When the tongue and mouth are just rubbing at the hot chicken, the tactile phase becomes very clear. You dare not to fully dig in, because of the heat.
The chewing phase:
When you then dare to chew and really enclose the food properly with your tongue and palate, the mouthfeel changes as the chicken, rice and sauce stick together into one body.
The subsequent phase:
After you have swallowed, the aftereffect arises. How do your mouth and throat feel? Do you experience coolness, dryness, heat, or sliminess? Your mouth is empty but the food may have left an increased temperature in the mouth, created dryness, or left a burning spice experience.
The psychological phase:
Finally comes the psychological aftereffect. How does it feel after the meal? This phase can, for example, be described as refreshing, thirst-quenching or saturating. In the case of the hot chicken stew, a feeling of general saturation and well-being is felt. A fatty sauce and other calorie-rich accessories may make you drowsy.
The Ketchup experiment
It is not surprising that taste, aroma, and mouthfeel may be a bit confusing.
On the one hand, there are food experiences that are difficult to classify. For a long time astringency (the dry sensation in the mouth that tea or red wine can give rise to) was considered a taste experience but is now considered to be a mouthfeel.
On the other hand, the three interact with each other. Depending on how we process the food in the mouth (for example, how vigorously we chew), taste and aroma substances are released in different amounts.
This interaction is illustrated in an interesting experiment that the food researcher Ole G. Mouritsen and the chef Klavs Styrbæk describe in the book Mouthfeel: How Texture Makes Taste.
The experiment creates two types of ketchup. The only difference is the processing; one is made completely smooth and the other has pieces that offer some chewing resistance. Although the same amount of the same kind of ingredients is used, test subjects, who taste both, say that they taste completely different.
Is it possible?
The answer is both yes and no.
Both kinds of ketchup taste the same, but the mouthfeel differs so much that you think they taste different. It’s easy to believe that the two ketchup varieties are actually different varieties with different ingredients. Strange, right?
As the coarse ketchup requires chewing, aromas are released that affect our taste and smell. As a result, the taste seems to be enhanced, but in fact, it is the mouthfeel and aromas that together make us experience a taste change.
Mouthfeel is greatly affected by our expectations.
In their book, Mouritsen and Styrbæk talk about another experiment in which participants were offered a puree. The question was how many of the participants could identify that the puree was made from cabbage.
Only five percent succeeded.
Cabbage is difficult to recognize. But even familiar ingredients are a challenge; only every other participant recognizes tomatoes without the help of the mouthfeel.
Another example regarding the significance of expectations is from a food fair in the Netherlands. Sacha and Cedrique are two guys who turn McDonald’s food into snacks that passersby can taste in the belief that it is an organic fast-food alternative. The response? Look here:
The tastiest food we’ve eaten
In an old issue of a youth magazine, a little girl is telling us about her school trip. The fireplace goes out during the night in the old cottage. In the morning, it is minus seven degrees Celsius and the packed food has frozen and has become hard as a rock. The girl and her friends use an axe to split the spaghetti. Despite these hardships, the experience is described as fun and the food tasted wonderful after all the efforts.
It is easy relating to the girl’s story. We probably all have similar stories where simple and everyday food is transformed into the best we have eaten. Perhaps after a day at the lake, a sports activity or a mountain hike.
But as a food producer, the product must always maintain high quality. Not just during excursions and outdoor activities. Taste is still an important measure. But if you do not take into account the mouthfeel, it may not matter how good the flavours are. And when it comes to sugar substitutes, there is the risk that both taste and mouthfeel are compromised.
Sugar and mouthfeel
If you want to replace sugar, there are a number of alternatives. But it is another story if you want to replace sugar, and at the same time, maintain mouthfeel.
If sugar is removed to reduce calories and blood sugar levels, the sweetness can only be replaced with a high-intensity sweetener such as steviol glycosides. Three grams of the herbal sweetener is enough to reach the same sweetness as one kilogram of sugar. But then the sugar bulk and texture will lack, which contributes a lot to the mouthfeel. Therefore, something else is often needed to give the same mouthfeel.
Finding a combination of high-intensity sweeteners and other ingredients that give the same sweetness and mouthfeel is difficult. It is time-consuming and requires specialist expertise that not everyone has. Simply put: It is difficult (to put it mildly) to find the right combination and dosage.
In the e-book The Sweetening journey, we go further in exploring the challenges of replacing sugar with fewer calories but maintaining good quality products. If you have not already downloaded and read it, then it is time to do so. You find it here.
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