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If we put two substances having different taste on tongue simultaneously how it will taste? Does specific part of tongue is sensitive to specific taste?
The Taste Map of the Tongue You Learned in School Is All Wrong
Everybody has seen the tongue map – that little diagram of the tongue with different sections neatly cordoned off for different taste receptors. Sweet in the front, salty and sour on the sides and bitter at the back.
It’s possibly the most recognizable symbol in the study of taste, but it’s wrong. In fact, it was debunked by chemosensory scientists (the folks who study how organs, like the tongue, respond to chemical stimuli) long ago.
The ability to taste sweet, salty, sour and bitter isn’t sectioned off to different parts of the tongue. The receptors that pick up these tastes are actually distributed all over. We’ve known this for a long time.
And yet you probably saw the map in school when you learned about taste. So where did it come from?
That familiar but not-quite-right map has its roots in a 1901 paper, Zur Psychophysik des Geschmackssinnes, by German scientist David P Hänig.
Hänig set out to measure the thresholds for taste perception around the edges of the tongue (what he referred to as the “taste belt”) by dripping stimuli corresponding to salty, sweet, sour and bitter tastes in intervals around the edges of the tongue.
It is true that the tip and edges of the tongue are particularly sensitive to tastes, as these areas contain many tiny sensory organs called taste buds.
Hänig found that there was some variation around the tongue in how much stimulus it took for a taste to register. Though his research never tested for the now-accepted fifth basic taste, umami (the savory taste of glutamate, as in monosodium glutamate or MSG), Hänig’s hypothesis generally holds up. Different parts of the tongue do have a lower threshold for perceiving certain tastes, but these differences are rather minute.
The problem isn’t with Hänig’s findings. It’s how he decided to present that information. When Hänig published his results, he included a line graph of his measurements. The graph plots the relative change in sensitivity for each taste from one point to the next, not against other tastes.
The taste map: 1. Bitter 2. Sour 3. Salt 4. Sweet. (MesserWoland via Wikimedia Commons, CC BY-SA)
It was more of an artistic interpretation of his measurements than an accurate representation of them. And that made it look as though different parts of the tongue were responsible for different tastes, rather than showing that some parts of the tongue were slightly more sensitive to certain tastes than others.
But that artful interpretation still doesn’t get us to the taste map. For that, we need to look to Edwin G Boring. In the 1940s, this graph was reimagined by Boring, a Harvard psychology professor, in his book Sensation and Perception in the History of Experimental Psychology.
Boring’s version also had no meaningful scale, leading to each taste’s most sensitive area being sectioned off in what we now know as the tongue map.
In the decades since the tongue map was created, many researchers have refuted it.
Indeed, results from a number of experiments indicate that all areas of the mouth containing taste buds – including several parts of the tongue, the soft palate (on the roof of your mouth) and the throat – are sensitive to all taste qualities.
Our understanding of how taste information is carried from the tongue to the brain shows that individual taste qualities are not restricted to a single region of the tongue. There are two cranial nerves responsible for taste perception in different areas of the tongue: the glossopharyngeal nerve in the back and the chorda tympani branch of the facial nerve in the front. If tastes were exclusive to their respective areas, then damage to the chorda tympani, for instance, would take away one’s ability to taste sweet.
In 1965, surgeon TR Bull found that subjects who had had their chorda tympani cut in medical procedures also reported no loss of taste. And in 1993, Linda Bartoshuk from the University of Florida found that by applying anesthesia to the chorda tympani nerve, not only could subjects still perceive a sweet taste, but they could taste it even more intensely.
Modern molecular biology also argues against the tongue map. Over the past 15 years, researchers have identified many of the receptor proteins found on taste cells in the mouth that are critical for detecting taste molecules.
For example, we now know that everything that we perceive to be sweet can activate the same receptor, while bitter compounds activate a completely different type of receptor.
If the tongue map were correct, one would expect sweet receptors to be localized to the front of the tongue and bitter receptors restricted to the back. But this is not the case. Rather, each receptor type is found across all taste areas in the mouth.
Despite the scientific evidence, the tongue map has burrowed its way into common knowledge and is still taught in many classrooms and textbooks today.
The true test doesn’t require a laboratory, though. Brew a cup of coffee. Crack open a soda. Touch a salted pretzel to the tip of the tongue. In any test, it becomes clear the tongue can perceive these tastes all over.
This article was originally published on The Conversation.
Steven D Munger, Associate Director, Center for Smell and Taste Professor of Pharmacology and Therapeutics, University of Florida. This piece was coauthored by Drew Wilson, communications specialist at the University of Florida Center for Smell and Taste.
How Your Tongue Works
While the tongue's muscles guide food between the teeth and shape it so that it's digestible, the peripheral sense organ is perhaps better known for its role in the perception of taste. The tongue not only detects gustatory (taste) sensations, but also helps sense the tactile, thermal and even painful stimuli that give food its flavor.
Most people mistake the bumpy structures that cover the tongue's surface for taste buds. These are actually papillae: goblet-shaped elevations that sometimes contain taste buds and help create friction between the tongue and food. Taste buds are smaller structures, tucked away in the folds between papillae. Every taste bud is made up of basal and supporting cells that help maintain about 50 gustatory receptor cells. These specialized receptors are stimulated by the chemical makeup of solutions. They respond to several primary tastes: sweet, salty, bitter, sour, umami (savory) and fat, which some scientists claim might be a sixth taste. When a stimulus activates a gustatory cell, the receptor will synapse with neurons and send an electrical impulse to the gustatory region of the cerebral cortex. The brain interprets the sensation as taste.
Each gustatory receptor cell has a long, spindlelike protrusion called a gustatory hair that comes into contact with the outside environment. The hair extends from a small opening, or taste pore, and mingles with molecules of food introduced by saliva. The saliva solution contains digestive enzymes that help break down foods chemically. Saliva is secreted by three major salivary glands -- the parotid, submandibular and sublingual glands -- as well as other small salivary glands contained within the tongue and mouth.
Aside from the tongue's ability to detect gustatory stimuli, it also perceives temperature and the complex tactile sensations that food scientists call mouth feel. The tongue, along with the rest of the mouth, helps determine a food's texture, oiliness, chewiness, viscosity and density.
In the next section, we'll learn about how the tongue functions in speech.
Engineering students at Purdue University and the University of Michigan used licking machines to get to the bottom of the eternal question: "How many licks does it take to get to the Tootsie Roll center of a Tootsie Pop?" Purdue's machine averaged 364 licks while Michigan averaged 411. However, these robot tongues may have been inefficient. Hungry humans took 252 licks at most in other Tootsie tests [source: Wired].
Lessons for the 5 Senses Science Experiments
The Five Senses
As humans, we have five tools that help us explore the world around us – sight, hearing, smell, taste, and touch. Our eyes, ears, nose, mouth, and skin gather a lot of information about the world they help protect us and help us enjoy life! Not everyone is born with all of these senses. Some people are born blind, or without being able to hear. Usually they learn to use the senses they do have better than people who have all five senses. A person who is blind may have an extra-good sense of hearing, for example. Some people also lose their sight or hearing as they get older.
Our vision is the strongest sense. As soon as you open your eyes every morning, you can see the things around you. You can watch a movie, or see a beautiful sunset, or run and play outside because of your eyes. How do our eyes work? We see color and movement because light enters our eyes and forms a pattern.
The little dark circle in the center of each of your eyes lets light in. It is called a pupil.
If you are in a dark place where no lights at all are on, can you see anything? No, you can’t, because our eyes need light to be able to see!
Once the light goes in, it hits a part inside at the back of your eye that is very sensitive to light. This part is called the retina. When light hits the retina, it makes an upside-down picture of whatever you are looking at.
The picture is sent to the brain through the optic nerve. Nervesare tiny parts in your body that act as messengers. They send signals to your brain of what they can feel, or sense. Together, the many parts inside our body that sense what is around us are called the nervous system.
When the brain receives the picture from your eyes it gets turned around very quickly so that you see it the right way instead of upside-down!
This happens automatically whenever your eyes are open. Seeing is like breathing you don’t even have to think about it, but you do it all the time!
If you look at your eyes in a mirror, you will see eyelids and eyelashes which protect your eyes by keeping dust out.
Every time you blink (about once every six seconds) your eye is working to keep out bits of dirt and dust so tiny you can’t even see them.
Another important sense is hearing. Our ears allow us to enjoy things like being outside, talking with our friends, and listening to music.
Being able to hear also helps protect us from danger, for example, we can hear if a car is coming when we are crossing the street.
A human with normal hearing can tell the difference between 1500 sounds!
Our brain is able to pick out really high sounds and really low sounds. If you have a piano or keyboard, try playing the lowest note, and then the highest. The piano has 88 sounds – our ears are able to pick up a much wider range of sounds, from soft to loud, low and high. We are able to hear the chirping of an insect on a summer’s day, and the clashing of cymbals at a band concert.
Sound is caused when objects vibrate (move back and forth very quickly).
Vibrations create sound wavesthat can travel in all different directions through air, water, and lots of other materials.
When sound waves are spread out, the sound we can hear is quiet. When they are clumped together, the sound is much louder. When sound waves go into your ear, they hit your eardrum and make it vibrate. The tiny vibrations move through your ear like a light shining through a long tunnel until they get to some nerves at the end of your ear.
The nerves take them to your brain where they turn into the sound that you hear!
The third lesson of our 5 senses science experiments focuses on smell. Did you know that without our noses we couldn’t enjoy things like our favorite meal cooking, or a bouquet of flowers?
Our nose also helps us know what we are eating.
This happens because as we chew our food, air is flowing from our mouth to the back of our throat.
When it reaches our throat, some air reaches the back of our nose. Our nose picks up the smell, and the signals are sent to the brain.
The full flavor (whether you like the food or not) is “tasted” by your nose as well as your mouth!
Our tongue can pick out four types of tastes – bitter, sour, sweet, and salty.
We can taste because of the tiny bumps called taste buds that are all over our tongue, and the top (or roof) of our mouth.
Taste buds are connected to nerves in the tongue, and they pick up the signals that are sent to the brain so you can taste what you are eating.
The inside of our mouth can also feel the foods we are eating, so if you don’t like a food, it might not be the flavor, but the texture that “tastes” gross.
Our skin is very sensitive to what it comes in contact with. All over our skin are tiny receptors that are connected to nerves.
These receptors are spread all over our body, allowing us to feel, but there are more receptors on our hands and face then anywhere else.
Our hands are able to act like a second pair of eyes, providing a detailed picture for the brain.
Our sense of touch is important in many ways. One way it protects us is by setting off reflexes.
Have you ever tried to grab something that was really hot, and then quickly let go? Your senses told your body it was hot, and you reacted very quickly, even before your brain realized it felt hot.
Our sense of touch allows us to enjoy things like petting a cat or dog, and running through the sprinkler on a hot day.
Nerves– tiny parts in your body that send messages to your brain about what they sense, allowing you to sense things.
Nervous System– all of the nerves in your body connect to your spinal cord (which run through your backbone), which connects to your brain. This very complex system is what allows you to sense things.
Sound Waves– tiny back and forth movements, called vibrations, that can travel through air and other things like fabric and water. Sound waves are usually blocked by solid objects, such as walls.
Use this worksheet with the “Take a Walk!” activity.
Afterwards, your kids or students can make a picture list of all the things they remember from their 5 senses science experiments walk.
Taste buds are found elsewhere too – in the roof of the mouth and even in the throat
Today we know that different regions of the tongue can detect sweet, sour, bitter and salty. Taste buds are found elsewhere too – in the roof of the mouth and even in the throat. As well as detecting the four main tastes, each taste bud can also detect the most recently discovered taste, umami – the taste that makes savoury foods like parmesan so more-ish.
These tastes are not all detected in the same way. For a long time it was assumed that the receptor cells inside our taste buds could spot any taste, but this idea was overturned by Charles Zuker who runs a lab at the University of California, San Diego. Over the years he and his team identified different receptor cells for sweet, sour, bitter and umami and just one taste – salty – was preventing them from completing the set. But in 2010 they succeeded in identifying that receptor too.
We have approximately 8,000 taste buds and each contains a mixture of receptor cells, allowing them to taste any of our five tastes.
Different regions of the tongue are able to recognise all five different tastes (Credit: Alamy)
Messages about taste are sent to the brain via two cranial nerves – one at the back of the tongue and one at the front. As a further counter to the idea that different parts of the tongue detected different tastes, it was shown that even if the front nerve, the chorda tympani, is anaesthetised, people can still taste sweetness, which in the traditional tongue map is found at the tip of the tongue.
The next mystery has been how the brain decodes these messages delivered via the cranial nerves. In 2015 a team at Columbia University found that mice have specialist brain cells which respond to each taste.
So it is true that we have specialist equipment for each taste. But rather than being clusters of taste buds in particular regions of the tongue, they are specialist receptor cells with matching neurons in the brain, each attuned to a particular taste.
Different areas of the tongue can taste anything, but although some regions are slightly more sensitive to certain tastes, those differences, in Steven Munger’s words are “minute”.
All content within this column is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. The BBC is not responsible or liable for any diagnosis made by a user based on the content of this site. The BBC is not liable for the contents of any external internet sites listed, nor does it endorse any commercial product or service mentioned or advised on any of the sites. Always consult your own GP if you're in any way concerned about your health.
How Hypertaste adds value
Hypertaste proves that a portable device could be capable of rapid fingerprinting of complex liquids – a capability currently lacking in the toolkit of chemical analytics. Industries and services that would benefit from such a technology range from industrial supply chains, food and beverages and environmental monitoring to the pharmaceutical and healthcare sectors, to name just a few.
As an example of the advantages of the Hypertaste combinatorial sensing approach, think of the supply chain safety from producer to consumer for packaged food and drinks. At present, once food and drinks are packaged, there is little ability to verify that the package actually contains what is on the label, apart from sending the product to a lab for testing. So, suppliers acting in bad faith may insert lower-quality products into the supply chain with little risk of getting caught, or counterfeiters may even fake a real product by adding the few analytes which are most likely to be tested for in a lab. Fooling a combinatorial sensing system such as Hypertaste is much harder as there is no single substance on which the identification relies, and it is more difficult for wrong-doers to access the sensor training parameters which provide the “key” to interpreting the chemical fingerprints.
In the long term, we also envision using Hypertaste in fingerprinting even more challenging liquids, like those occurring in the life sciences. Sampling a person’s urine, for example, could help provide an assessment of the metabolomic fingerprint, which may be understood as the sum of all small molecules present in a living organism. As this rich chemical information is constantly changing depending on factors such as lifestyle and nutrition, metabolomic fingerprinting can be thought of as creating a snapshot of a person’s health.
Besides possible applications in diagnostic or preventive medicine, such a tool could also allow sub-grouping of patients in clinical trials for new drugs by matching the individual responses of patients to a treatment with information on their personal metabolomes. The spectrum of possible applications is vast and spurs the imagination. We are confident that, through forthcoming refinements, the use of AI-assisted, portable chemical sensors will meet the needs of many industries when it comes to the fast and mobile fingerprinting of complex liquids.
Patrick W. Ruch, Rui Hu, Luca Capua, Yuksel Temiz, Stephan Paredes, Antonio Lopez, Jorge Barroso, Aaron Cox, Eiji Nakamura, Keiji Matsumoto, A portable potentiometric electronic tongue leveraging smartphone and cloud platforms, 2019 ISOCS/IEEE International Symposium on Olfaction and Electronic Nose (ISOEN)
Yet another controversial "taste" is our registering of metals, such as gold and silver, in the oral cavity. Some Asian cultures place gold and silver leaf, as it's called, atop curry dishes and candies, while Europeans fancy a bit of these metallic foils on pastries. The silver foil garnish is known as "vark" when used on Indian sweets, as in the picture above.
Although usually tasteless, such garnishes are sometimes reported as having a distinctive flavor. Researchers have shown that this sensation might have something to do with electrical conductivity, in effect giving the tongue a little zap. "If you cut a copper penny in half, expose the zinc core and put it on the tongue, you get a whopping metallic taste," said Harry Lawless, a professor emeritus of food science at Cornell University. "It's like a little battery, with a drop of saliva – you get about 550 millivolts."
Lab tests have failed to turn up a metallic-taste receptor, Lawless said, and it remains unclear if electrical conductivity or something more is going on for those shiny culinary embellishments. "We're leaving the door open," Lawless said.
The jury is still out on whether our tongues can taste fat, or just feel its creamy texture. Clearly, many of us enjoy fatty foods, from well-marbled steak to pretty much fried anything.
"Fat is a tremendous source of calories," said Linda Bartoshuk, a physiological psychologist at the University of Florida "Eating fat is encouraged by our brains to have us survive."
Mice can taste fat, research has shown, and it looks like humans can too, according to a 2010 study in the British Journal of Nutrition. The study revealed varying taste thresholds for fatty acids – the long chains that along with glycerol comprise fats, or lipids – in participants.
Intriguingly, the subjects with the higher sensitivities to fat ate fewer fatty menu items and were less likely to be overweight than those with low sensitivity.
Bartoshuk, who was not involved in the research, noted that fatty acids "tend to taste bitter in the mouth," and she thinks touch fibers in the taste buds sense the creamy thickness of non-broken-down fat globs instead.
What can neurogastronomy do?
Many of America’s largest food companies pump excess sugar, salt, and fat into packaged and processed foods to enhance flavor and optimize consumer bliss at the cost of their health [10,11]. However, understanding how non-taste-related sensations impact flavor could drive healthy eating without any additional cost. A healthier diet would reduce or curb the growing obesity epidemic and the risks affiliated with being obese, such as artery disease, type 2 diabetes, hypertension, and heart attacks . Furthermore, neurogastronomy findings are already being incorporated in some restaurants to enhance the dining experience.
For instance, the restaurant The Fat Duck in England serves a seafood dish called “Sounds of the Sea” that comes complete with sand, foam, seaweed, a conch shell, and a pair of iPod headphones. Part of the dining experience involves using the headphones to first hear the sounds of the waves and seagulls before eating, which customers claim makes the fish taste fresher and better .
In addition, neurogastronomy studies may help patients who have lost the ability to taste or smell. This challenge was already put to the test at the first international neurogastronomy conference held at the University of Kentucky in November of 2015. At this conference, top chefs competed to create the perfect dish that would best appeal to all of the senses of two chemotherapy patients .
By building on knowledge about how textures, smells, appearances, and sounds of food affect flavor perception, the chefs were able to create highly enjoyable dishes for both patients . Thus, science is starting to uncover how all of our senses contribute and work together to give us the perception of flavor. In the future, we may be able to entice kids to love broccoli by presenting it together within a perfect combination of color, texture, sound, and smell.
Sucrose, or table sugar, tastes sweet. Obviously, this sweet flavor is always the same, correct?
Actually, our experience of the sweetness of sucrose can be influenced by our sense of smell. If you put sucrose into a mixture that gives off a fruity or floral odor, this mixture will be experienced as tasting more sweet than a mixture with the same level of sucrose that gives off a savory odor. We learn this through association.
Therefore, there is more to our perception of food than just the four “tastes.” Flavor is the total experience of all the taste sensations coming together to produce a unique experience for each food. This is much more complex than the simple act of detecting the individual tastes. People often say that losing your sense of smell causes you not be be able to taste, or to not to be able to taste as well. What they really mean is that your ability to experience flavor can be greatly diminished.
The key to understanding why people think plugging your nose blocks your sense of taste is in how the brain handles flavor as opposed to taste as well as understanding that taste and flavor are two different things. So now it’s time for more science (neuroscience, isn’t this blog advanced?)
Why do I have a bitter taste in my mouth?
A bitter or bad taste in the mouth can be a normal reaction to eating pungent or sour foods. However, when the taste lasts for a long time or happens unexpectedly, it can be concerning.
Taste is a complex sense that can be affected by many factors, including poor dental hygiene, dry mouth, or pregnancy.
Treating a persistent bitter taste involves treating any underlying conditions, but people can manage the unpleasant taste with some simple home remedies in the meantime.
In this article, we cover 13 possible causes of a bitter taste in the mouth. We also discuss symptoms and treatments.
Share on Pinterest Dysgeusia is the medical term for an altered taste in the mouth.
A persistent altered taste in the mouth is known medically as dysgeusia. This taste is described as unpleasant and can last for a long time until the underlying cause is treated.
People with dysgeusia may experience a constant taste that they often describe as one of the following:
The taste can be distracting, and may even make it hard to taste other things while eating or drinking. A person may still have the taste even after brushing their teeth. They may also experience other symptoms depending on the cause.
Many of the causes of a bitter taste in the mouth are not serious. However, the symptoms can be irritating and may interfere with a person’s regular diet or their enjoyment of daily life.
The following conditions can cause a bitter taste in the mouth:
A dry mouth, also known as xerostomia, occurs when the mouth does not produce enough saliva. Because saliva helps reduce the bacteria in the mouth, having less saliva means that more bacteria can survive.
People with xerostomia feel a sticky, dry feeling in their mouth. This could be caused by factors such as medications, pre-existing disorders, or tobacco use. A person can also get dry mouth if they have a stuffy nose because breathing through the mouth can dry it out.
People with a persistently dry mouth should talk to their doctor for a proper diagnosis.
Poor dental hygiene can also cause a bitter taste in the mouth. It may also cause an increase in cavities, infections, and gum disease or gingivitis.
Many common dental issues can be avoided by regularly brushing and flossing the teeth. Some people may also find that using a tongue scraper helps to clear up some symptoms.
Using an antibacterial mouthwash in between brushing may help keep foul-tasting bacteria to a minimum. A range of mouthwash is available for purchase online.
A bitter or metallic taste in the mouth is a common complaint during the first trimester of pregnancy.
The hormones in the body fluctuate during pregnancy. This variation can affect the senses, which can cause specific cravings and make some foods or smells seem disgusting.
Many people who are pregnant also notice a metallic, bitter, or tinny taste in their mouths. This can be annoying, but it usually goes away later in the pregnancy or after giving birth.
Burning mouth syndrome
Burning mouth syndrome is a condition that causes a burning sensation in the mouth. The feeling can vary, but many describe it as similar to eating spicy peppers. Alongside, some people may also experience a bitter or rancid taste in their mouth.
The symptoms of burning mouth syndrome may appear sporadically, but it can also be chronic and last for a long time.
Some people with the syndrome may have difficulty eating or drinking, while others may find that this relieves their symptoms.
Women going through menopause may also experience a bitter taste in their mouth. This could be due to lower levels of estrogen in the body, which can lead to a secondary condition, such as burning mouth syndrome. It may also be due to a persistently dry mouth.
GERD or acid reflux
Gastroesophageal reflux disease (GERD) or acid reflux may be the source of an unwanted bitter taste in the mouth.
These conditions occur when the muscle or sphincter at the top of the stomach becomes weak and allows acid or bile to rise up into the food pipe.
GERD tends to irritate the food pipe, causing a burning sensation in the chest or abdomen. It can also bring about a foul or bitter taste in the mouth, which may persist as long as the other symptoms.
A yeast infection in the mouth often causes white spots or blotches to appear on the tongue, mouth, or throat. It may also cause a bitter or unpleasant taste that may persist until the infection is treated.
Pine nut syndrome
In some people, eating pine nuts may cause a bitter or metallic taste in the mouth. This often happens 1 to 3 days after eating pine nuts. The syndrome also shows no other symptoms and goes away after a couple of weeks.
Stress and anxiety
High stress and anxiety levels can stimulate the stress response in the body, which often alters a person’s sense of taste. Anxiety can cause dry mouth, which frequently results in a bitter taste.
Like our other senses, taste buds are directly connected to the nerves of the brain. Damage to the nerves can cause a change in how a person experiences tastes.
Nerve damage can result from a head injury or conditions that include the following:
Medications and oral supplements
In some people, certain medicines, supplements, or medical treatments may cause a bitter taste in the mouth. This may be because the medicines taste bitter or because chemicals in them are excreted into the saliva.
A person should consult their doctor to find out if their medications could be causing a bitter taste.
Medications that may lead to a bitter taste include:
- certain antibiotics
- some cardiac drugs that contain minerals or metals, such as copper, iron, or zinc
- lithium drugs
Certain illnesses, including sinus infections or colds, can be accompanied by a bitter taste in the mouth.
During these illnesses, the body sends out inflammatory proteins to capture harmful cells. These proteins may also affect the tongue and taste buds, which could make a person experience a taste in their mouth that is more bitter than normal.
A person who is undergoing cancer treatment may experience an off taste in their mouth when eating or drinking.
Chemotherapy and radiation treatment may irritate the taste buds in some people, which may cause even simple things, such as plain toast or water, to have a bitter or unpleasant taste.
What Factors Affect Taste Perception? (with pictures)
Some of the factors that affect taste perception are the color of the food, its texture, temperature, and smell. The taster's age, if he has a certain disease, and his stress and exhaustion level may also affect the way taste is perceived. The human tongue is able to detect five basic tastes: salty, sweet, bitter, sour, and added in 2002, umami, a word which in Japanese means “delicious.” Each of these different tastes has a certain receptor on the tongue, and when a compound triggers the receptor, the brain recognizes the taste. Taste perception is not only affected by the taste buds, however, and food scientists are studying ways different factors affect the taste of different foods and beverages.
One of the most well-known altering factors of taste perception is smell. Simply put, the flavor of a food can be defined as the taste of the food combined with the smell of it. In fact, if a person has a cold that blocks the nose or another issue that affects the sense of smell, the flavor of food is diminished or may become blander. Not only can smell affect taste, but it can also cause memory recollection. For example, a person may be reminded of his childhood home if he smells a certain fragrance.
Texture can also be a factor that affects taste. Some studies have suggested that a thicker drink can taste less sweet or have a less intense flavor than a thinner one, even though the concentrations of sugar or flavoring have not been changed. In practice, food scientists and manufacturers may be able to use this fact to reduce the amount of salt in food without changing its taste. They may simply need to alter the texture.
Another factor that affects taste perception is color. Studies show that a brighter or more intensely colored food can seem to taste different than a blander colored food even when there was no change in the flavor compounds. Similarly, two drinks that have the same coloring may taste the same to a person even though one is sweeter. There was even an experiment done in the 1970s in which scientists allowed people to eat food that looked normal under a certain light. When the light was changed and people saw that they were eating blue steak and green fries, some of them started to get sick.
Food temperature can also affect taste perception. Warmer foods usually taste more intensely flavored than cold foods even though the concentration of flavor is the same. For example, ice cream may taste sweeter when it is melted, and beer more bitter. Similarly, coffee can be more bitter when it is hot, a taste that is desired in that particular drink. By simply cooling down or heating up a food, a person may be able to alter his taste experience of that food.
A person’s physical self can also affect taste perception. As a person ages, the ability to taste and smell food also diminishes. In addition, one study showed that a person with renal disease or cancer may experience taste distortions, called dysgeusia. A person’s stress level and physical fatigue can also affect how something tastes. One study showed that after mental exercises, some people had shortened durations and lowered perceptions of the bitter, sour, and sweet tastes while the duration of the sour aftertaste was shortened after physical exercise.