Do you know about Taste and Smell? 👃

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Speaker 1: You're listening to sleep Tight Science. Did you know that your sense of smell plays a big role in how things taste. In fact, if you hold your nose while eating a piece of chocolate, it might not taste as good as when you're able to smell it. Hmmm, Hello friends, and welcome back to sleep Tight Science, a bedtime show that answers your questions about science. In this episode, we will learn about the wonderful world of taste and smell and answer some of the questions you our listeners have submitted about this topic and others. So if you are comfortable, let's start exploring the amazing senses that let us savor the flavors of our favorite food and sniff out the sense that surround us every day. Taste and smell are linked senses. Both detect chemicals either in food or in the air. Together, they enable people to appreciate a wide range of flavors. The tongue is the organ of taste and has about ten thousand taste buds on its upper surface. Buds can detect five basic tastes, sweet, sour, salty, bitter, and umami, which means deliciousness in Japanese. Remember bitter tasting foods may be poisonous and can be spat out. Taste buds are found on the sides of tiny bumps called papilli that cover the tongue. There are three main types of papilli. Fungiform papilli that resemble mushrooms and can be found scattered across the tongue's surface, circumvallate papilli, which can be found at the back of the tongue. There are seven to fourteen of these large ridged popilli at the back of the tongue, and threadlike philiform papilli, which have no taste bud buds and help to grip food during chewing. When dissolved food chemicals reach a taste bud, sensory cells send nerve impulses to the brain. The tongue has different areas for tasting sweet, bitter, salty, and sour flavors. The tongue also has receptors for heat and cold, and pain receptors for spicy foods. We will talk more about why eating spicy hot food can make us feel like we're experiencing physical heat later. Our sense of smell helps us enjoy food and avoid harmful substances In the air or in food. We can detect over ten thousand different odors because we have about ten million smell receptors located in the upper part of our nasal cavity. These receptors are found in two patches of epithylium or lining, each the size of a postage stamp. Each receptor contains up to twenty hair like cilia. When air is breathed in, molecules dissolve in a watery mucus and bind to the cilia. Smell dominates taste. A cold can make food taste flavorless. You may have heard some super big words scientists like to use, but don't worry. We will simplify things at different times throughout the show. Learning new words takes a long time, so we need to be patient sometimes. Did you know that there's a fruit called durian that smells so bad to some people that it has been banned from some public places. That's right. Durian has a very strong and pungent odor that some people say smells like a combination of rotten onions, gym socks, and gasoline. But here's the amazing part. Even though some people can't stand the smell of Durian. Others absolutely love it and think it tastes delicious. Before we continue with this topic, we have some questions to answer that are somewhat unrelated. We love getting your questions, so please keep sending them to us. Oliver Age eight in May in Westchester, Ohio asks why does honey crystallize? Honey is one of our favorite things, and many of our friends in sleep tight stories like it too. Did you know that honey never spoils? Honey has a very special property that makes it last forever as long as it's stored in a sealed container. In fact, archaeologists have found pots of honey in ancient Egyptian tombs that are still good to eat even though they are over three thousand years old. Honey lasts so long because it contains very little water and a lot of sugar. Bacteria and other microorganisms need water to grow, so without it, they can't thrive in honey. Honey also has enzymes that create hydrogen peroxide, a natural antiseptic that helps kill any bacteria that might be present. Honey is made up of lots of tiny sugar molecules, and sometimes these molecules like to stick together and form crystals. This is called crystallization. When honey crystallizes, it becomes thicker and more solid, like a spreadable jelly. Other factors that can contribute to honey crystallization include temperature, the type of flour nectar the honey was made from, and how the honey was stored. Cooler temperatures can speed up the process of crystallization, while warmer temperatures can slow it down. The good news is that even though crystallized honey might look a little different, it's still perfectly safe to eat. Thank you. Oliver Amelia, age six from Nottingham, England asks why does moldy food change color? Mold is a type of fungus that likes to grow on food that's been left out too long or is it stored properly. It needs food, moisture and warmth to grow, and it can grow super fast. When mold grows on food, it releases chemicals that can change the food's color and texture. For example, bread that's gone moldy might have blue or green spots, and fruit that's gone bad might look brown and squishy. The mold is made up of tiny threads called hiphie, which are too small to see with our eyes. But when enough of these hiphee grow together, they can form a visible patch of mold that we can see and recognize. While mold might not be very appetizing to look at, it's actually a natural part of the environment. It helps break down or gain matter like food and leaves. But it's always important to make sure we store our food properly and throw away anything that's gone bad. To avoid getting sick from eating moldy food with your parents, you could try an experiment that shows how mold grows on bread when it's moist and not stored properly. First, dampen a slice of bread with water and put it in a sealable plastic bag. Next, seal the bag and write the date on it. Leave the bag in a warm, dark place for a few days. Open the bag after a few days and observe the bread to see if any mold has grown on it. Remember to always wash your hands after handling moldy bread or any any other food that's gone bad. Thank you. Amelia Sloane Conkle, age six, from Wisconsin would like to know if fairies are real. We love to write about fairies and think they exist, at least in our imaginations, but unfortunately, there is no scientific evidence to prove that fairies actually do exist. However, we can still enjoy the stories and legends about fairies and imagine what they might be like. Sometimes it's fun to believe in magical creatures like fairies. They can inspire us to be creative and use our imaginations. We especially like the kind of fairies that wave their magic wand and make us sleepy when we are in bed. Thank you, Sloan. Taste and smell our two senses that work together to help us enjoy food and drinks. When we eat or drink something, it goes into our mouth, and our taste buds help us taste different flavors. We have about ten thousand taste buds on our tongue and in our mouth, and they can detect five main tastes, sweet, sour, salty, bitter, and you mommy. Taste buds can detect different flavors because they have special cells that respond to different chemicals in food. When these cells are activated, they send signals to our brain to tell us what we are tasting. Smell is important for our sense of taste. When we smell food or drinks, we're actually smelling tiny molecules that are released into the air. These molecules enter our nose and stimulate special receptors that send signals to our brain to identify different smells. Our brain then combines the information from our taste buds and our sense of smell to create the sensation of flavor. In fact, some studies suggest that up to eighty percent of what we perceive as taste from our sense of smell. Why does eating spicy food sometimes make us feel like we're experiencing physical heat? You know how, when you eat really spicy food, like hot sauce or peppers, your mouth starts to feel like it's on fire. That's because spicy foods contain something called capsaicin. Capsaicin is a chemical that tricks your brain into thinking your mouth is being burned by heat. Your mouth has tiny little pain receptors, sensors that send signals to your brain when they sense something hot or spicy. These receptors are normally activated when you eat something physically hot, like soup or pizza that just came out of the oven. But when you eat something spicy the capsaicin in it makes those same receptors think they're being burned by heat even though there's actually no heat there. So your brain gets the same message whether you eat something really spicy or something that's physically hot, and that's why eating spicy food can make you feel like you're experiencing physical heat. Isn't that cool? Even though your mouth might feel like it's on fire, eating spicy food isn't actually hurting you. So the next time you eat something really spicy, just remember that your brain is being tricked into thinking it's being burned by heat even though it's not. What makes certain foods smell really strong, like onions and garlic, One reason is that some foods contain volatile compounds, which means they can easily evaporate into the air. When you cook or heat up these foods, the volatile compounds are released into the air and you can smell them. For example, when you bake bread, you can smell the aroma of the yeast and the other ingredients as they cook. Another reason is that some foods contain sulfur compounds, which can have a strong odor. Foods like broccoli, cabbage, and cauliflour contain sulfur compounds that give off a strong smell when cooked. Lastly, some foods simply smell strong because of the way they are prepared, and foods that are fermented or aged, like cheese and kimchi, can have a strong smell because of the bacteria and yeas that are used in the fermentation process. Onions and garlic in particular, contain a compound called alison. This compound is what gives them their strong, distinctive smell. When you chop or crush an onion or garlic, it releases the alison into the air. This is why you can smell it so strongly in the kitchen when you're cooking with them. But why does alison have such a strong smell. Well, it turns out that alison is the defense mechanism these plants use to protect themselves from animals and pests. The strong smell helps to repel insects and other creatures that might want to eat the plant. Interestingly, not everyone can smell the strong odors of onions and garlic. Some people have a genetic variation that makes them less sensitive to certain compounds in these foods. This means that while some people might be able to smell the strong aroma of onions and garlic from across the room. Others might barely notice it at all. Why does chewing gum lose its flame after a while? This is a question I've wondered about for a while. When you first put a piece of gum in your mouth, it's full of delicious, sweet flavor. But as you chew it, something interesting happens. The sugar molecules and flavor chemicals in the gum start to break down and dissolve in your saliva. As this happens, the concentration of flavor molecules in the gum decreases, so you start to taste less and less of the flavor. In other words, the flavor is literally being chewed away. But it's not just the breakdown of the flavor molecules that causes the loss of flavor. The act of chewing also plays a role. Chewing causes the release of saliva, which helps to break down the flavor molecules and spread them around your mouth. This means the flavor molecules are being spread out over a larger area, so you're less likely to taste them as strongly. Another factor that contributes to the loss of flavor is habituation. When you're exposed to the same flavor for a long time, your brain starts to get used to it and doesn't respond as strongly. This is why something that tastes really sweet at first might start to taste less sweet after a while. Fun facts. Cats have a special organ in their mouths called the Jacobsen organ, which helps them to detect and process smells that humans can't detect. Some people claim that eating a lot of garlic can repel vampires, but did you know it can also repel mosquitoes. That's because garlic contains compounds that mosquitoes find repulsive. The spiciness of chili peppers is measured on the Scullville scale. The hottest pepper in the world is the Carolina Reaper, which has a Skullvill rating of over two million. Some animals, like dogs and mice, have a much better sense of smell than humans. In fact, a dog's sense of smell is so strong that it can detect a tea spoon of sugar in a million gallons of water. Taste buds only live for about ten days before they are replaced by new ones. That means that your sense of taste is constantly changing. Smelling coffee can actually help to clear your nasal passages and improve your sense of smell. Your nose can detect over one trillion different sens that's more than ten times the number of colors your eyes can see. Skunks are famous for their ability to spray a smelly liquid as a defense mechanism. But did you know that skunks can actually control the direction of their spray with amazing accuracy. They can even spray backwards over their heads. Have you ever noticed that some people have really stinky feet. That's because feet have a lot of sweat glands, and when sweat combines with bacteria, it can create a smelly odor. Whales can communicate over long distances by making sounds humans can't hear. These sounds, which are often called whale songs, are thought to be a form of communication that's similar to our sense of smell. In this episode, we learned some about taste and smell and how the two senses work together. We looked at our tongue and saw the different kinds of papillae that are found on our tongue and talked a little about what they do. We learned that our tongue has different sections that taste different things like sweet bitter, salty, and sour. We looked at our nose and talked about the smell receptors located inside and what they can do to help us. We also talked about honey, mold and fairies. This episode was made with questions from Oliver, Amelia and Sloane. Thank you to Elias and Miles, Ada and Owen and his sister as Lynn. We hope to use your ideas in future episodes. We love getting your feedback on our show. If you have any feedback, please send it our way, and also we would love it if you left us a review. Wherever you listen to podcasts, your review might help others decide to listen to our show too. If you'd like to send us your questions, please send them to Hello at sleeptightscience dot com. Thank you and sleep tight