How Does The Tongue Perceive Tastes And What Are The Main Ones
Have you ever wondered how our tongue is able to perceive flavours? Let's see how the taste buds work and what the main tastes are.
You're eating a delicious piece of chocolate and you pause for a second to think to yourself: "But how can I perceive these tastes and flavours ? How does our tongue understand that I'm really eating chocolate?" The answer lies in the taste buds of the tongue which, when they come into contact with chocolate, send a signal to our brain. In this article we see how the tongue perceives tastes.
How does the tongue perceive taste
The tongue is an organ with motor and sensory functions. Thanks to its movements it helps us chew , swallow and make articulate sounds. It also allows us to perceive , through the taste buds , the taste of food. In fact, when our tongue comes into contact with a substance, the receptors found in the taste buds manage to encode the "character" that defines that substance through a series of processes that lead to our brain. In this way we will have the sensation of sweet, bitter, sour (or sour), salty and the so-called umami (if you don't know what it is, we'll explain it shortly!).
Initially it was thought that each taste could only be perceived in a specific area of the tongue . In reality this is not the case , tastes can be perceived in every district of the language, only that some areas need a greater quantity of, for example, a bitter taste to codify this sensation.
The five flavours
Let's take a brief overview of how the tongue perceives the five tastes starting from the least known one, umami.
Umami is the taste of monosodium glutamate, typical of fermented products such as soy sauce and Parmesan cheese. Other very umami foods are tomatoes, roast meat, meat broth and seafood. Our tongue recognizes this taste thanks to the presence of the amino acid glutamate ; from here starts the process of translating the signal that brings this information to our brain . Umami is the typical taste of oriental cuisine , it is no coincidence that it means "tasty" in Japanese.
Substances that evoke salty taste contain sodium ( Na + ). Table salt, for example, is composed of an ionic bond between sodium and chloride (NaCl). It is precisely through the so-called " sodium channels " of the lingual mucosa that the process of "coding" the salty taste sensation begins.
The sour, the bitter and the sweet
The molecules that trigger the acid sensation are related to the presence of hydrogen ions ( H + ) which in turn cause a series of reactions that lead to the transmission of the signal at a nervous level. Even bitter and sweet follow specific decoding processes based on the molecules they contain.
Some studies report the existence of a sixth taste called " kokumi " which characterizes foods such as garlic and onion . It is certain that our tongue is able to perceive this "sensation" thanks to specific receptors, but kokumi is not yet recognized as a real taste.
There are also very recent studies that are investigating whether there is a " fat " taste that could be linked to a particular gene. Everything is still being analyzed but could have great implications for the understanding of some eating disorders and diseases such as metabolic syndrome .
How the perception of taste has changed
But why is sweet taste often preferred to bitter or salty to sour ? It's all about survival instincts .
In fact, the world of taste is affected by the evolutionary drive of mankind. For example, the observation that bitterness and acidity are often unpleasant sensations on the palate is closely linked to the fact that in their natural state various substances harmful to humans possess this characteristic. The rejection of these flavors therefore represents a real instinctive defense system of the organism against poisoning ! On the contrary, the sensation of " sweet " is often sought after (even beyond what is necessary…) because it is linked to the presence of sugar, the primary and most immediate source of energy for man.
What is flavor and what is the difference with taste
Well, now that we understand what taste is and how our tongue can perceive it, you may be wondering what flavor is.
Well, let's start by saying that the words "taste" and "flavour" are often used as synonyms. There are actually five tastes and they are perceived by the tongue: salty, sweet, bitter, sour and… umami . The flavors , on the other hand, are many and represent the characteristics that distinguish a food or a drink. They are perceived thanks to a set of elements, including smell .
The moment we take a bite, we begin to perceive the texture, temperature and organoleptic characteristics of the food inside the mouth . In particular, temperature influences flavor by regulating and modifying the action of sensory receptors by inhibiting or activating them. But the most important element is the smell of the food that rises from the mouth into the nose going to stimulate the olfactory cells . It is precisely the sense of smell that largely determines the flavor of the dish. Anyone involved in tasting knows this well.
Aroma, texture, temperature, tactile sensations, images and colors are the characterizing elements of each dish. What do they have in common? None of these are perceived only with the mouth. Sensory experience begins much earlier than we normally imagine and the way a dish is presented has almost the same importance as the elements that make it up. It all begins with the vision of the food that is presented, through particular reflex circuits which, starting from the visual image, anticipate and set in motion the digestive mechanisms such as salivation (which of you already has a watering mouth?) and peristalsis (those mumbles that you can listen to when you are hungry).