Eating is, with the forgiveness of others, the great pleasure of life. Experiencing the infinite nuances of flavors that gastronomy offers us is an experience that we all enjoy. And, like everything that happens in our body, feeling the flavors of food is pure chemistry.
The pleasure of eating is possible thanks to the sense of taste, which has, in the tongue, its sensory organ. In this language we find more than 10,000 taste buds formed by neurons capable of assimilating and processing the chemical information of what we eat and then send this information to the brain, where we will experience the taste itself.
But how many flavors are there? The variety of flavors is practically infinite, but traditional (and more recent) research points to the fact that all of them are born from the combination of some basic flavors: sweet, salty, bitter, acid, spicy, astringent, fatty and umami.
Sure some of them sound familiar to you but others are more unknown. And it is normal, since some have been described more recently based on studies in physiology and neurology. In today's article, then, we will rescue these investigations to describe not only the functioning of the sense of taste, but the particularities of these 8 flavors.
Tongue, taste buds and flavors - who's who?
As we have already mentioned, absolutely everything that happens in our body is pure chemistry. And, of course, the sense of taste and the experimentation of flavors also respond to chemical phenomena. But in what way? Let's go step by step.
Taste is, together with sight, hearing, touch and smell, one of the five senses. In this context, the sense of taste is defined as the set of neurological processes that have their origin in the tongue, specifically in the taste buds, where some Chemoreceptor neurons are capable of converting chemical information from food into electrical messages capable of traveling to the brain through the nervous system so that, once there, these signals are processed and we experience the flavor in question.
The sense of taste, then, has its sensory organ in the tongue. We are facing a structure of a muscular nature that belongs to the digestive system, with a cone shape and a length of about 10 centimeters with the important function not only of mixing food during chewing, but also of harboring said sense of taste.
The tongue is anatomically more complex than it may appear at first glance. In fact, it is composed of some 24 different structures that, working in a coordinated way, make possible not only the experimentation of taste, but also the detection of the temperature in food, digestion, chewing, swallowing, the fight against bacteria. and even speech.
Even so, as we are in the world of flavors today, we will focus exclusively on those structures directly associated with the sense of taste. And for this, we must speak, yes or yes, of the famous taste buds.
The tongue contains about 10,000 taste buds, but what are they? The taste buds are small bumps present on the mucous membrane of the mouth and that make the existence of the sense of taste possible.. They are really the physiological structures that allow us to feel (although experimentation actually happens in the brain) the flavors.
These taste buds have a kind of cavities inside which are known as taste corpuscles, which are chemoreceptor neurons capable of converting chemical information from food into nerve messages.
When the organoleptic molecules of food come into contact with the tongue, these molecules enter the cavities of the taste buds; and once there, via the taste corpuscles, they come into contact with the nervous system. These neurons read the properties of the molecules that have entered the body and, depending on their structure and which molecule it is, they will generate an electrical impulse tailored to the chemical information they have processed.
And once we have electrical information, these messages can travel, through a process of synapses (communication between neurons) and through the nervous system, to the brain, the organ that will process the electrical messages where the chemical information is encoded and allow us to experience the flavors. Flavors that, as we will see, depending on which papillae have been activated, will be of a specific nature.
What are the basic flavors?
It has become very clear that the sense of taste is a true feat of biology. Thanks to the coordinated action of the 10,000 taste buds and its sensitivity when it comes to capturing subtle differences in terms of the structure of the organoleptic molecules, we can feel an infinity of flavors, which is what makes eating one of the greatest pleasures.
Even so, despite this vast range of flavors, the truth is that, depending on which papillae are working, we can describe some basic flavors. Traditionally, it was believed that there were four (sweet, salty, bitter and sour), but the latest research suggests that there could be more. We want to make it clear that there is no scientific consensus, since we are facing something difficult to study. Even so, we offer you those that have the most support on a neurological level. Let us begin.
Surely one of the most loved flavors. Still, the exact mechanisms that allow us to process a food as candy remain, in part, a mystery. Let's see what we know for sure.
The foods that taste buds perceive as sweet are usually carbohydrates or carbohydrates (hence what contains sugar, sucrose and fructose is perceived as sweet), in addition to, of course, sweeteners. Even so, certain amino acids (present in protein foods) such as serine, alanine and glycine are also processed as sweets.
It also seems that the taste buds in charge of detecting those organoleptic molecules linked to the sweet taste are the fungiforms, which are those found throughout the length of the tongue, although it is at the tongue tip where there is a greater concentration.
The salty flavor is another of the greats. And, in this case, we do know better its neurological and chemical foundations. The salty taste comes from the intake of low molecular weight salts (those of high molecular weight are usually linked to the bitter taste), being common salt (NaCl) the clearest example. We all (or almost all) cook with this salt.
In this case, those responsible for the salty taste are the foliated papillae, those that are found in the frontmost part of the tongue and on its edges. These taste buds are sensitive to the presence of ions from these salts.
In these taste buds there is a salty taste receptor known as ENaC (Epithelial sodium channel), which is a set of proteins that allow the passage of specific ions. In this case, the soluble ions from salts, being the sodium ion (Na +) and the potassium ion (K +) the most frequent. Thanks to this passage of alkaline ions, the nervous messages are turned on that will allow the brain to interpret that what we eat is salty.
A taste, perhaps, less loved. Even so, it is important to know that bitter taste experimentation is one of the most important evolutionary strategies at the taste level. And is that having it seems to be associated with survival, because poisons stimulate this flavor. In this way, it serves to alert us that something is surely harmful. An explanation of why it is a flavor that you do not usually like.
But what is its physiological nature? It seems (there are those who say it is a myth) that the goblet papillae are the ones that are linked to their experimentation. These taste buds are found in the rearmost region of the tongue and can process many nuances of bitterness.
In this case, the molecules that turn on the mechanisms associated with the bitter taste are the high molecular weight inorganic salts (low were associated with salty) such as magnesium or copper salts. An unpleasant taste for some but it is still a true feat on a physiological level.
The sour taste is another of the loved and hated equal parts. In this case, the mechanisms that ignite the acid taste experimentation are somewhat different. Like bitter, it is often perceived as unpleasant because some toxic substances produce these flavors.
There are no specific taste buds linked to flavor (perhaps goblet are the most associated, but it is not clear), but there are receptors on the tongue capable of detecting hydronium ions (H3O +) that are formed when there are acidic substances (acids) in the presence of water, as in the mouth. Thus, acidic substances react on the tongue giving rise to this taste. It is important to emphasize that the intensity of the acid flavor is not always linked to a lower pH.
We enter controversial terrain. And it is that spicy really is not a flavor. Why? Because their experimentation does not come from the activation of neurons present in the taste buds, but from neurons associated with pain. Spicy is a pain, not a taste.
But we talk about him because he is very interesting. The spicy sensation is due to capsaicin, an organic chemical present in the fruits of different plants and which stimulates the thermal receptors of the skin, including, of course, those of the mucous membranes of the oral cavity.
When capsaicin is present in our mouth because we have eaten, for example, a jalapeño, the threadlike papillae are activated. These filiforms are not gustatory since they do not have chemical receptors, but they do have thermal receptors. They are the papillae that are responsible for detecting the temperature of the food.
Capsaicin, then, makes these threadlike papillae excited, so spicy foods literally make them the neurons of these papillae send the information to the brain that there is fire in our mouth.
These last three flavors are little known and little studied, so there is little information about their neurological nature. The astringent or acrid taste was described for the first time in India (in the East it is known, but in the West not so much) and refers to the sensation of dryness and even gritty in the mouth.
Astringent foods, in contact with our tissues, retract them, which causes this sensation of dryness or lack of hydration. The organoleptic molecules that can stimulate this astringency are present, for example, in red wines (tannins are what trigger this sensation), tea or dates.
A very recent "discovery" flavor. In 2006, scientists at the University of Burgundy, France, discovered that there were different taste buds on the tongue than others and that they had never been described.
These new taste buds appeared to have a specific receptor for lipids, that is, fats. For this reason, it is believed that one more new flavor should be added: adipose. The fatty taste would be the one linked to foods rich in fat.
We close our list with the umami flavor. Described for the first time in Japan at the beginning of the 20th century, umami would be another of the basic flavors, being the flavor linked to meats, although its origin was associated with the taste of "delicious foods", as indicated by the Japanese word from which it comes.
But what do we know today about the umami flavor? Apparently, this taste is due to the perception of monosodium glutamate, a chemical present in meat, fish, seafood, edible mushrooms, cheeses (especially Parmesan), soybeans and certain vegetables such as tomatoes.
Umami is a subtle but lingering aftertaste that is difficult to describe but can be defined as that distinctive meaty taste that induces salivation and enhances the flavors of other foods. It seems that all taste buds are capable of detecting glutamate associated with umami flavor.