The tongue is an organ, and a pretty weird-looking one, when it comes down to it. The surface of our tongue is covered with tiny bumps which, when looked at under a microscope, are actually pointy. There are three different types of papillae, of different shapes and sizes. What they all have in common though, is the tastebuds they contain. Tastebuds are made from a combination of cells—basal cells, columnar cells these are structural cells and between 10 and 50 taste receptor cells.
These have tiny hair-like structures called microvilli, which are basically nerve-endings that interact with the chemicals from our food. This interaction activates a protein, which in turn causes other messenger chemicals to be created. The receptor cells are renewed every 9—10 days. The number of tastebuds people have can vary greatly.
The average adult has between 2, and 8, tastebuds, but some people have larger, and fewer, tastebuds while others have many more smaller tastebuds. However, there are different types of taste receptors, that are each activated by a different suite of chemicals to elicit the various taste sensations we perceive. A taste cell only has one type of receptor, but each tastebud contains a combination of cells that express each type of receptor. The taste receptors for sweet, bitter, sour and umami are actually proteins produced and coded for by particular genes in our DNA that are found on the surface of the cells.
They are activated when they sense the presence of particular chemicals, triggering the sequence of cascade reactions and message sending described above. The salt receptor is called the epithelial sodium Na channel ENaC , which is essential a membrane that allows for the transport of sodium ions to certain cells in our body. There are thought to be specific taste receptors corresponding to the five main types of taste humans can perceive:. The way a food smells is also important to our overall eating experience.
As we chew, volatile compounds are released and travel from the back of our mouths to our noses, where they stimulate our olfactory system.
For example, the flavour of vanilla is entirely dependent upon its aroma—it has no actual taste, but we perceive the flavour when its aroma hits our nose.
There other sensations besides taste that take place in our mouths. These too, are driven by the activation of receptors triggered by certain chemicals in the food we eat. The TRP-V1 protein is activated by heat—a mouthful of hot soup, perhaps, but also by capsaicin hot chillies , piperine black pepper and allyl isothiocynanate hot mustard.
The texture and consistency of the food—how it feels in our mouths—is also important to how we perceive its taste, and whether or not we like it. Differentiating between useful nutritious food and poison is the main driver for our sense of taste. Similarly, our love of sugar comes from a fundamental need for energy and we need proteins to provide the amino acids essential for growth and tissue replenishment.
Neither of these nutrients were as readily available back in the early days of human evolution as they are to us today. We all have our favourite foods, be they chocolate, ice cream, cherries or stinky cheese, and most of the time, the reason we like or love it, is because of its taste—that little thrill our tastebuds send up to the pleasure receptors in our brains.
But if we all have the same basic tastebuds, and our tastebuds and the messages they send to our brains are fundamentally controlled by a series of chemical reactions, then why don't we all like and hate the same foods and flavours? There are several genes for all the bitter receptors, and how many of these we all have can vary from person to person. The sliminess of okra can make others recoil. Humans can taste more than four flavors on their tongue.
Depending on how narrowly you define "taste", there are between five and several dozen independently experienced sensations on the tongue, according to the book " Taste and Smell: An Update " by Thomas Hummel. The seven most common flavors in food that are directly detected by the tongue are: sweet, bitter, sour, salty, meaty umami , cool, and hot.
Note that "cool" and "hot" tastes do not refer to actual low or high temperatures being present, but rather to foods that chemically trigger a sensation that is similar to cool or hot sensations.
Sweet flavors come from things like candy and fruits. It is no wonder that this is a taste that even babies gravitate to.
Furthermore, when used in a combination, sweet complements well with the other basic tastes. Adding sweetness such as a drizzle of sweet balsamic glaze to a traditionally salty vegetable dish like roasted brussel sprouts would take it to the next level.
The simplest taste receptor in the mouth is the sodium chloride receptor. Salt is a necessary component to the human diet and enhances the flavor of foods. Interestingly enough, when people cut back on salt in their diets, taste buds can adjust again and adapt to be satisfied with less. As a flavor enhancer, adding salt to traditionally sweet dishes is necessary to amplify the sweet notes.
A pinch of salt is core to most baked dessert recipes. Even if it is not listed in the ingredients, sprinkling some sea salt flakes or smoked salt over holiday ginger bread cookies brings out the sweetness of the sugar and enhances the ginger flavor. Sourness is a taste that detects acidity. These taste buds detect hydrogen ions from organic acids found in foods. The mouth puckering sensation is common in citric fruits such as lemons and oranges, as well as tamarind and some leafy greens.
The sour taste can also be obtained from foods soured through fermentation such as sauerkraut and yogurt, or through the addition of vinegar. Many salad dressings feature vinegar as a key ingredient, which is a perfect way to add sour notes.
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