Taste, flavor, odor, perception and a range of buzz words are used to describe what we eat and drink. In this episode of Tiny Matters, Sam and Deboki break down what they mean, how they relate to human health, and how to find ways of making foods you don’t like more appealing.
Transcript of this Episode
Sam Jones: OK Deboki, tell our listeners what you are holding right now.
Deboki Chakravarti: I have a grapefruit Polar 100% natural seltzer. It is my preferred seltzer and my preferred flavor which is ruby red grapefruit. It is apparently made with natural flavors and it has no juice in it, no sweeteners, no sodium, but it is very, very tasty.
Sam: OK so now I want you to crack it open. Take a sip and then describe to listeners what you’re experiencing.
Deboki: So my first experience, because I poured it into a glass, was the feeling of gas hitting my nose. I had it in the fridge so it felt kind of cool. It has the sharpness of the bubbles, but also with all of that is the grapefruit. It’s subtle, it’s not overwhelming. It’s not like having a grapefruit juice where you’re overwhelmed with the fruit flavor or anything, but it's definitely there.
Sam: Yeah, subtle but there. What’s so interesting about this, and the reason I’m asking you to drink this grapefruit Polar Seltzer while we’re recording, is that there isn’t grapefruit juice or syrup in there. So why does it taste like you’re drinking something with a splash of grapefruit? Odor. For a lot of seltzers, it's just odor molecules that you're picking up on that makes you think you're drinking something with grapefruit or coconut or melon added to it when in fact it’s just aroma and fizzy water.
Deboki: Welcome to Tiny Matters. I’m Deboki Chakravarti, and I just had my mind blown by a seltzer fact.
Sam: And I’m Sam Jones. And when I first learned that it kinda felt like well duh makes sense but also ‘what I had absolutely no idea!’. The person who clued me in to this was Stephanie Hunter, a postdoctoral fellow at the Monell Chemical Senses Center in Philadelphia.
Stephanie Hunter: So like seltzers, they use that aroma component to make it, through our experience, it makes it seem sweet then because we associate like these fruity flavors with sweetness, so then you can just add in the aroma and it'll seem sweet to you.
Deboki: Taste, flavor, odor, perception and a range of buzz words are used to describe what we eat and drink. In this episode of Tiny Matters we’re going to break down what they mean and talk about how they relate to our health. You’ll even get tips for making foods you don’t like more appealing, plus a semi-healthy and surprising cake recipe. So yeah, stay tuned.
Sam: As we often do on Tiny Matters, let’s start with the basics. What is taste?
Stephanie Hunter: Taste refers to the sensations of sweet, sour, salty, bitter, and umami. And we detect these when specific chemicals bind to the receptors in the taste buds, which are all in our mouth.
Deboki: A lot of times you’ll hear flavor and taste used interchangeably, but flavor is actually the combination of input from three sensory systems: taste, olfaction or smell, and somatosensation.
Somatosensation is a physiological process that allows you to detect things like texture — crunchiness or mushiness for example, and it also includes a thing called chemesthesis. Chemesthesis is the detection of chemical compounds that cause feelings like tingling, burning, and cooling. For instance the burning you feel when you eat a chili pepper or the cooling you get when you eat something minty.
Sam: And actually, when you eat or drink something it can get even more complicated, because some of your tongue receptors — the proteins that stick off of cells that detect the sweet, salty, bitter, sour, umami — those same receptors can be found in other parts of your body, including in your stomach.
Devin Peterson: I'm a coffee drinker and one of the things that happens with coffee and maybe overconsumption of coffee at times is you can get heartburn.
Deboki: That’s Devin Peterson, a professor in the Department of Food Science and Technology at The Ohio State University and the director of the Flavor Research and Education Center, as well as the Foods for Health Initiative.
Devin Peterson: And so what that's been linked to actually is bitter compounds in the coffee will trigger receptors in your stomach. It's not triggering bitterness in your stomach, but it’s just that they're also reactive and trigger gastric juices that are in your stomach, and results in more heartburn.
Sam: How wild that the receptors on your tongue that help your brain detect bitterness also exist in your stomach but send a very different message to your brain which is “oof heartburn.” So for anyone who wants to dive deeper on that, they’re called T2 receptors and they are truly all over the place, even in your heart where their exact role is not clear yet. I have nothing to add to that, just thought it was really interesting. OK, let’s get back to flavor.
Deboki: If you’re eating food and you remove taste, smell, or somatosensory input from the flavor equation, it dramatically changes the experience. And I think it’s fair to say that smell is probably the variable we’ve heard about most over the last few years.
Stephanie Hunter: There's a lot of people who have lost their sense of smell. It's actually not a new thing. We've been hearing about it a lot lately because of the pandemic, but even before the pandemic, it was estimated that about 20% of the population had some type of smell disorder. So now there's just millions more people who have long-term smell disorders because of COVID-19.
I'm doing a lot of work in people who have lost their sense of smell. They're missing that huge component of flavor and food isn't tasting as good anymore. We don't just eat for the healthfulness of the food. So we're eating for the flavor and we're eating foods with flavors that we like. So when that flavor's gone with smell loss, this lack of flavor perception really impacts their quality of life.
Sam: I’ve gotten COVID a couple times at this point and I did lose my sense of smell once. It was terrible. It felt like the food I was eating or stuff I was drinking had no flavor at all. It was actually this very eerie thing when I first noticed it. I made coffee, like I do every day, and started drinking it and then realized I couldn’t smell it. Then I just started frantically walking around my kitchen smelling everything and nope, nothing. I knew it was really bad when I had to pick up dog poop and couldn’t smell it. Which I guess you could call a silver lining.
Deboki: That sounds so disorienting. I would be so confused. It sounds pretty miserable except for the dog poop part.
Devin Peterson: Food provides a lot of enjoyment in our life. And so you think about important events we all gather, you know, for important events around food we enjoy. It's an important part of our culture and human behavior.
People generally eat what they like. And if you're going to set up dietary guidelines and say, okay, these sorts of food patterns are more idealized for health and wellness, you have to consider what we'll call the consumer traits.
Deboki: Consumer traits, meaning what consumers choose to buy and why. Stephanie actually clued us in to something called the Food and Health Survey, where every year the results show that flavor is the number one driver of what foods people choose to buy.
Stephanie Hunter: And that's been rated number one for the past decade, and it's rated higher than the healthfulness of the food, the convenience, the sustainability. So people find the flavor to be a lot more important in what they're going to buy and then consume compared to all these other factors. So it's really one of the primary drivers of food choice.
Deboki: So if you’re trying to eat healthier but you really don’t like the taste of a lot of those foods, it’s going to be a serious challenge.
A lot of both Devin and Stephanie’s work looks at how the flavor of foods could be improved so that people are more inclined to eat them. For instance, a recent study from Devin’s lab looked at pea protein. And maybe you’ve seen pea protein powders at the supermarket. Pea protein is a pretty versatile source of protein that’s both sustainable and nutritious and not likely to cause an allergic response like some milk-based protein products. We actually use it in my house because my husband’s vegan, but the ones we get are pretty heavily flavored.
Sam: And having that heavy flavoring is probably a good thing, because pea protein isn’t so great on its own. Not just in my humble opinion, but consumers generally are not fans. So to be able to make a product more enticing, knowing what’s in it — what could be causing that ‘pea soup smell’ — could be really helpful in leading to modifications that would make people more likely to use it. Devin and his colleagues were able to identify 21 different pea protein aromas by using a combination of chemistry techniques like gas chromatography/mass spec that let you separate out individual molecules by size and charge.
Science is a lengthy process and making changes in a consumer product takes a lot of time, but it would be cool if some of that data helps lead to new and improved pea protein of the future.
Deboki: But we don’t all have hundreds of thousands of dollars of lab equipment to explore what aromas are in food that we find more or less appetizing. So what do we do if we want to expand our pallets?
Sam with Devin Peterson: For someone who would like to develop a taste for a certain food, say they're trying to eat a bit healthier, they want to eat broccoli more because they know it's good for them, where would be the place to start with that?
Devin Peterson: Dipping it in cheese?
Sam with Devin Peterson: <laugh> That's a good one.
Devin Peterson: <laugh> Okay. I tease you, but of course you see that in commercials. One of the things that really will influence perception of foods is how you're going to cook them. So there's many ways to prepare foods and to mix them with other ingredients and to cook them in different ways. You know, whether I'm going to microwave it, which is probably quite bland, or put it in an oven or sauté it, right? Those are very different. And so frying or just sautéing even has a different temperature that these products are experiencing, and actually generates different types of flavor compounds. You may less like one preparation, you might be more inclined to enjoy another.
How you prepare these ingredients and how you mix 'em with, say, soups other sort of preparation methods can really help you to maybe find that sort of sweet spot, so to speak, and allow you maybe to broaden that palette that is more idealized with your dietary goals.
Sam: Deboki, is there a healthy food that you just cannot stand and do you think ‘maybe I’ll try it’? With or without cheese?
Deboki: I really, really hate the taste of papaya. It’s one of my least favorite foods of all time. I don’t know that I can prepare papaya in a way that’s different. But I guess the closest thing is that I don’t really mind green papaya. So maybe that’s just what it is, is I can do a different form of it.
Sam: Mmm just easing yourself in, or not and just sticking with green papaya?
Deboki: And especially with papaya I don’t have to eat it, I can have other fruits, so I think I’m OK. At least I’m OK with it for now.
Devin and more suggestions for us, but first a quick break.
We want to tell you about a cool podcast we think Tiny Matters listeners will be interested in. It’s called The Weirdest Thing I Learned This Week and it’s from Popular Science.
If you enjoy interesting, informative, and — most importantly — weird scientific discussions like ‘Have you ever heard about the time a bunch of scientists tried to turn George Washington into a Zombie?’, then you need to check out this podcast.
Sam: The Popular Science team is a seasoned crew of science and technology journalists who are using their decades of experience to bring you the strangest scientific facts.
Every episode, host Rachel Feltman and guest scientists like Bill Nye and Mary Roach, break down weird-but-true facts about everything from the world’s most illegal cheese to the real reason people are afraid of clowns.
If you want to laugh and learn more about the science behind all the weird things happening all around us every day - make sure to head over and subscribe to The Weirdest Thing I Learned This Week on Apple Podcasts, Spotify, or wherever you’re listening. We’ve also put a link in the episode description.
OK, now back to the show.
Deboki: So Devin shared how the way you prepare a food, whether you saute it or bake it, or do something else to it could totally change the food’s flavor and how much you like it. But he also had a few more suggestions for people who want to start incorporating different foods they don’t typically like into their diets.
Devin Peterson: I think you could also broaden where you get your ingredients. There are sometimes, for example, more heirloom tomatoes that are growing right in a farmer's market, and different varieties can have quite a bit of variation in their attributes. And one you might like more and others you may like less. And so just to be aware of that. And I think that can give you at least a little bit more flexibility. And I would also go back to maybe putting them in more of a casserole or other dishes you may realize, like for example, I'm a big fan of a zucchini chocolate cake. And you would not think those go together, but that is to me a great combination.
Sam with Devin Peterson: Would you be open to — this is a side note — but would you be open to sharing that recipe with me? Because then I can actually put it in the episode description…
Devin Peterson: I would be happy to do so.
Sam with Devin Peterson: Okay. I didn't know if it was like a secret family recipe <laugh>
Devin Peterson: It's somewhere up the family tree, but I don't know that anybody is protecting it <laugh>
And you know, it doesn't sound like zucchini and chocolate go together, but they blend, right? Sometimes combinations really create new sensations in ways that are just advantageous.
Sam with Devin Peterson: Why do we sometimes change our minds about what we like? So for instance, I could not stand the taste of peanut butter as a little kid, but this morning I had a banana with peanut butter all over it for breakfast. I was happy to eat it.
Devin Peterson: So I'll give you another analogy. I was very averse to watermelon when I was young. And now I'm certainly a fan of watermelon and would seek it out. And so what that tells you is that part of what is our preference or things that we are driven towards to consume can change with experience. So aroma perception, particularly the aroma attributes of food, I would call more learned behaviors. And so your exposure to different foods and different experiences is ever changing in a way that starts to open up new opportunities for food consumption. And for me as I started to get maybe different experiences to other fruits and melons and then maybe brought in watermelon, I started to learn to appreciate it.
Deboki: So if you are someone who has lost their sense of smell or it is diminished for whatever reason, you might be wondering what you can do to get back some of the enjoyment that comes with eating. Stephanie had a couple suggestions.
Stephanie Hunter: A lot of times when people have a smell disorder, they'll rely on different strategies to help get some flavor back and to enjoy eating again. We often hear people focus on the texture of foods. So mushy foods aren't gonna be as palatable to them anymore, but more crunchy foods will, or more crispy foods will.
A lot of people will also focus on enhancing the different tastes of the food in that absence of smell to try to enhance some of the flavor. One thing that we notice, when people have a smell disorder, is that they'll add a lot more salt onto their foods just to get some flavor and some feeling back. And if this is maintained with long-term smell loss it could lead to other issues associated with excess salt intake.
So one thing I'm looking at is seeing if we can use a type of sensory strategy to make food palatable, but without needing to add some of these components to foods that could harm health. So there's been some previous studies in people who have a normal sense of smell where they find that adding capsaicin, so that spicy component of a chili pepper, can help enhance salt taste intensity without needing to add more salt. So the capsaicin and the odor from chili peppers can both enhance the salt taste intensity. So I wanted to see if this could also be some strategy that we could use in people with smell loss, if it’s also helpful for them to help enhance salt taste intensity.
So basically what we did is we recruited a bunch of people who had smell loss for 12 weeks or more and we gave them different soup samples, and we added three different levels of capsaicin to the soup. So there was none in it, or we added a low amount or a moderate amount, and then we had them sample these soups and we had them rate how flavorful they were, how salty they were, how spicy they were, things like that. And we found that just adding a small amount of capsaicin, so it was perceived to be low, it's not even outrageously spicy, can help enhance the salt taste intensity in these foods. And it also enhances the flavor perception.
There's all these diets that people recommend, but a lot of times people don't adhere to them because they don't like them. So you kind of have to incorporate some type of sensory component to it to make sure that it's still palatable in order for people to adhere to it long term.
Deboki: Understanding the delicate balance of a food’s taste, smell and somatosensation is not only helpful for eating more nutritious foods. It’s also key to finding alternatives to compounds that are not good for us and a major part of the American diet, like processed sugar.
Devin Peterson: There are probably other ingredients that might create what’s called mouthfeel or tactile cues that are similar to sugar and actually could then provide some sort of analogy to that sensation. It's not completely the same, but a way to fill in some of those missing pieces.
Sam with Devin Peterson: It makes me think like, people love soda. Could we somehow trick ourselves into being able to drink a fake Coca-Cola because of some sort of aroma compounds that are added mixed with a texture adaptation. I dunno, I’m sure that would be very difficult to do.
Devin Peterson: If you look at the industry and innovation for beverages for decades now, they've been trying to come up with a non caloric product. And they certainly are out there but I mean, there's still a lot of people that prefer the sugared product. And so part of the challenge there is that, one, sugar fills a very unique role in regards to perception and sweetness and even how it is perceived from a mouthfeel perspective, and it's hard to understand how do you do that without sugar? But there's also what's called post-ingestive behavior.
Deboki: So when sugar hits your tongue, you can sense that it’s sweet. But when it hits your stomach, it also activates something called “wanting” where you’re going to crave it and seek it out again. If you want to go on a sugar deep dive we have an episode from last year all about sugar, its impact on our bodies, and the debate surrounding if sugar is actually addictive. And I am of course biased but I think it’s pretty fascinating. We’ll link to it in the episode description.
Sam: After chatting with Devin and Stephanie I feel like I have this newfound appreciation for how complex flavor is. And how important it is for our health. And how we can kind of trick ourselves into trying new things by something as simple as sauteing or air frying or even combining healthy things with less healthy things to generate new delicious flavors. I’m ready to make that chocolate zucchini cake.
Deboki: For science.
Sam: For science. For my stomach.
Tiny show and tell time.
Deboki: Yeah, I think I'm going first this time.
Deboki: Okay. So this isn't really heavily related, but I now am rethinking my tiny show and tell in the context of what we've been talking about. So what I want to talk about is a deep sea freezer that these geochemists at the Japan Agency for Marine-Earth Science and Technology were working on, or have worked on, and they were testing it out. So basically the idea behind why you would want a deep sea freezer is that sometimes scientists want to study animals that live deep in the sea, but it's hard to bring those animals up to surface. The blobfish that we all know of as this blobfish does not actually normally look like a blobfish. Apparently it looks like a normal fish in its normal habitat, but as it's being brought up to surface, it just loses its form.
Sam: Oh, that makes me so sad.
Deboki: I know. It's so sad to think about. I mean, it's so weird looking and cute in a way, but you're like, man, we have really... I want to see actually what the blobfish-
Sam: I feel so emotional about the blobfish now.
Deboki: You can see the resemblance where you're like, oh, okay, it's got this weird triangular-ish face. It looks like a pyramidal sort of shape. It becomes the blob version of that once it's brought up to surface.
Sam: Oh, that's sad. Okay, poor guy.
Deboki: Yeah. So scientists have worked on these different tools to try to be able to bring animals up to surface that don't turn them into blobs, like pressurized collection chambers, but it still takes hours to bring these animals up to surface. And sometimes, especially for smaller and softer animals, they might start degrading in that time. So one of the ideas was can we design a freezer that will help minimize that damage?
So the scientists were able to create this freezer. It doesn't use liquid nitrogen or refrigerant to cool down. Instead, it uses something called the Peltier effect, which is basically a way to create a potential difference that then creates a temperature difference in the freezer. So it's super interesting, and they were able to demonstrate that it works. The reason why I was just thinking about everything we were just saying is because they actually, for this article that I was reading about it, they used it to make this little frozen orange treat. They made it 850 meters below the surface with this freezer. So now I'm like, huh, I wonder if that changes the flavor profile at all?
Sam: Oh my gosh, that's so interesting. So then the freezer is hanging out in the deep sea, but then ultimately, once you have the samples that you want, you bring it back to surface, but then they're sort of protected.
Sam: Oh, that's so interesting. Very cool. I hope for the blobfish that-
Deboki: For the sake of the blobfish.
Sam: Blobfish not so blobby if you leave him where he likes to be.
Sam: So mine also happens to be aquatic, but ancient aquatic. Really, I want to do this tiny show and tell, because the images that I saw I was completely blown away by. So researchers have discovered the fossilized vertebrae and ribs from about a 39 million year old whale, and they discovered these fossils in southern Peru. Yeah, it's like, whatever, there's lots of whales. But this was probably the heaviest animal that has ever lived, which I felt was tiny show and tell worthy. So today the blue whale has that title, but for comparison, so this ancient whale skeleton, just the skeleton, was likely around 15,000 pounds. But then based off of the 13 vertebra and ribs that they found, this whale could have weighed up to 750,000 pounds.
Sam: Yeah, just under that, I think they were saying the upper limit was something like 749,000-something pounds, which for context is I think three times the size of your average blue whale and is also somewhere around eight passenger jets or 15 semi trucks. So the image that really got me on this, it was just the vertebra, just seeing one of them and three people around it. It's like 200-something pounds for just a vertebra, and it's massive. It's huge.
Deboki: I want to see this vertebra.
Sam: Here, I'm sending you the link that I looked at. If you just scroll down a little bit.
Deboki: Oh my God, that is huge.
Sam: I know.
Deboki: That is one vertebra?
Sam: That is one.
Deboki: And there are 12 more?
Sam: Yeah, that they found, and then they also found, I guess, some ribs.
Deboki: Wow, you can build a home with those ribs, probably. Wow.
Sam: It's pretty wild. Just conceptualizing how big a blue whale is, I think is kinda hard, but then just thinking about something that could be a few times bigger is unreal.
Deboki: I don't think I even realized that blue whales were that big. I knew they were giant. I hadn't thought of them as that big. So yeah, being like, oh my God, there was something even bigger than that. Also, this illustration from this article of the whale is hysterical. It has this massive body that in the context of this illustration, it looks like it's just a fish in an aquarium almost because it's just so big relative to its surroundings in this illustration. Then it has these tiny little limbs that you're like, what do you do with those?
Sam: Yeah. I think truly, probably very little. We could have a whole conversation about how you have these terrestrial mammals that then came back into the ocean, and that's why we have whales and other mammals that have lungs that live in the ocean. So yeah, these are like, their appendages in this image, it's just hilarious. You're like, oh, you haven't been on land in a long time. It's been a while since you guys were hanging out on land.
Deboki: Well, thank you. My mind has been blown, again this episode, it started with seltzer and it's ending with whales.
Sam: Seltzer facts and massive whales.
Sam: Yeah, we bring everything at Tiny Matters. All right, cool. Let's wrap this thing up.
Deboki: Thanks for tuning in to this week’s episode of Tiny Matters, a production of the American Chemical Society. This week’s script was written by Sam, who is also our executive producer, and was edited by me and by Michael David. It was fact-checked by Michelle Boucher. The Tiny Matters theme and episode sound design are by Michael Simonelli and the Charts & Leisure team. Our artwork was created by Derek Bressler.
Sam: Thanks so much to Stephanie Hunter and Devin Peterson for chatting with us. We’ve left a link to that chocolate-zucchini cake recipe in the episode description. We’ve also left a link to the Tiny Matters coffee mug! If you want to support the show and look really cool drinking your morning cup of coffee, tea, juice — I mean you can even eat your chocolate zucchini cake out of it if you want — we’ve left a lin for you. You can find me on social at samjscience.
Deboki: And you can find me at okidokiboki. See you next time.
Chocolate Zucchini cake
¼ c. butter
¼ c. cocoa powder
½ c. vegetable oil
½ tsp. baking powder
1¾ c. sugar
1 tsp. baking soda
½ tsp. cinnamon
1 tsp. vanilla
½ tsp. cloves
½ cup buttermilk or sour milk
2 cups grated zucchini
2½ c. flour
½ c. chocolate chips
Directions: Preheat oven to 325°F. Cream together the butter and sugar. Then beat in the oil, eggs, vanilla and buttermilk. Sift dry ingredients together and mix into wet ingredients. Fold in the zucchini and chocolate chips. Bake in a greased and floured bundt pan or a 9x13 pan for 45 minutes.