Pod Insights Science Friday A Horn Of Potato Plenty | Adding Marbling To Fake Meat For An Extra-Realistic Bite About this episode Just in time for Thanksgiving, a potato researcher explains potato varieties, potato nutrition, and some tubular tuber facts. And, irregular, fatty marbling gives meat a unique texture. Recreating that in plant-based products isn’t easy.
Transcript 0:03 Speaker 00 Meat and potatoes are the stars of Thanksgiving, even if plant-based meat is on your table this year.
0:10 Speaker 01 We'll use a 3D printer to print like the fat-rich regions and the protein-rich regions, so it looks something like real meat.
0:18 Speaker 00 It's Thursday, November 28th. Happy Thanksgiving. You're listening to Science Friday.
0:27 Speaker 00 I'm Sci-Fry producer Shoshana Buckspam. To improve plant-based meat products, food scientists are getting creative with how to add a more realistic texture to the eating experience. One big challenge is marbling, how to get irregular fatty bits into a product that's made to be uniform. We'll get to that story in just a bit, but first, the humble potato and how it gets from the farm to your dinner plate. Here's guest host Kathleen Davis.
0:56 Speaker 02 We're talking about meat and potatoes. First, the humble potato of versatile vegetable, baked, roasted, fried, mashed. What can't they do? But how exactly do these tasty tubers end up on our tables? Joining me now to give us a crash course in the science of potatoes is my guest, Dr. Rhett Spear, Assistant Professor in the Plant Sciences Department at the University of Idaho, based in Aberdeen, Idaho. Dr. Spear, welcome to Science Friday.
1:27 Speaker 03 Hi Kathleen, thank you for having me.
1:29 Speaker 02 Well, thank you so much for being here. I want to start with a little bit of potato 101. Can you tell us a little bit about how they grow?
1:38 Speaker 03 Absolutely. So unlike a lot of plants that grow from an actual little seed that you plant in the ground, most potatoes are what they call vegetatively propagated. So what that means is if you take a potato and you cut it into pieces and throw it in the ground, that it will grow another plant. And that new plant will be genetically identical to the parent plant.
2:03 Speaker 02 Okay, so let's back up here. So if I have like a pile of potato peels and other bits, is it possible that a potato would grow from that pile?
2:15 Speaker 03 It depends on how big those bits are. If you have a decent sized piece, and as long as, you know, you look at the potato and you see those little divots on the outside of it that we call eyes. Those eyes are actually where the stems grow from. So if you have a piece that's big enough and it has at least one eye on it, you can plant that that piece. And as long as the conditions are are right, you know, it's not too cold, it's not too wet, not too dry. That little piece will grow into a new potato plant.
2:46 Speaker 02 Okay, so I think most people are familiar with maybe two distinctly different potatoes that they might come across in the grocery store. We've got the white potatoes and we've got sweet potatoes. What is the difference between the two?
3:00 Speaker 03 So if you go back far enough into their their family tree, so to speak, they are very, very distantly related, but more importantly, sweet potatoes are more part of the the morning glory family. And potatoes are in the Solanaceum family. So their potatoes are in the same family as like tomatoes and tobacco and eggplants.
3:23 Speaker 02 Mm hmm. Okay, so let's go back to our our good old white potatoes. How did we arrive at the common potato varieties that we see in the grocery store? So I'm thinking Russets, Yukon Golds, Redskin Potatoes. How did we kind of come to this conclusion of these are the ones that we're going to find at basically every grocery store?
3:44 Speaker 03 So a lot of that comes down to, you know, there's been something in their in their development that has been beneficial to the farmer or to the consumer. So a lot of these white potatoes, a lot of them will store fairly well and for a long time. Potatoes like Yukon Gold, you know, they have a really good taste and they're visually appealing. But most of these potatoes, while they do have lots of good things that have got them into the grocery store, oftentimes they'll have, I don't know if you want to call them speed bumps in their growth that that could be a bigger hindrance, but the the farmers know how to grow them. They've been growing them for long enough that they know how much fertilizer they need, how much water they need, when to plant and harvest them, and what they need in the season.
4:29 Speaker 02 You have, I think, one of the coolest jobs out there. You help to develop new potato varieties. So as an expert in this, what makes for a good new potato?
4:41 Speaker 03 So we're always looking for things like efficiency and sustainability. We want to see potato varieties that will turn a better profit for growers. So an example of this would be we're looking for maybe potato varieties that use less fertilizer or are less impacted by stresses like heat or water. Things that will, you know, make that that variety easier to grow or better to grow or something that will help the industry to be better.
5:14 Speaker 02 And I suspect that you also want those potatoes to taste good, right?
5:18 Speaker 03 Oh, of course.
5:19 Speaker 02 So what are the factors that actually contribute to the flavor of a potato?
5:25 Speaker 03 So there's a lot of things that will actually contribute to the flavor. Anything from the soil that it's grown in to the different chemicals and volatiles and things that are actually in the potato that vary by variety. So if you eat a russet potato, it's probably going to taste different than if you eat a Yukon Gold or a red or a purple potato.
5:49 Speaker 02 So we talked a little bit about the people who are actually growing these potatoes. How does weather affect the growing process for potatoes?
6:00 Speaker 03 So weather is a huge factor when it comes to growing potatoes. The plant, based on the weather, can kind of start growing and stop growing. I don't know if that makes sense, but if it gets too cold, the plant kind of just, it doesn't grow as fast. And if you have potato tubers that are already growing at that point, you know, they stop receiving nutrients also. So when the potato starts growing again, and especially if it starts growing really fast, you could have one end of the tuber that's a lot smaller than the rest of the tuber. And if you have tubers that maybe received some kind of stress in the middle of the growing season, like it got too hot, or the farmer didn't get the water on or something like
6:41 Speaker 03 that, you might have that plant stop growing or grow very slowly. And once it can start growing at its full rate again, you might have a tuber that looks like a dumbbell.
6:52 Speaker 02 Okay. I don't know if I've ever seen a dumbbell shaped potato, I have to say.
6:56 Speaker 03 Well, quite often they'll they'll cull those out, they'll pull them before they get to the store because they're not visually appealing. Nobody wants to buy that kind of potato.
7:05 Speaker 02 We talk about climate change a lot on this show because it tends to affect everything. Does climate change play a factor into how you are thinking about developing new varieties of potatoes into how these potatoes might grow?
7:21 Speaker 03 Absolutely. So we really want to find varieties that are less susceptible to like heat stress or water stress, that they kind of like they can handle it a little bit better than some of the varieties that we currently use. So we do trials at the university where we'll stress these varieties on purpose, like we won't give them enough water, or we'll give them not enough fertilizer. And we'll see at the end of the season how that affects the yield and the quality of those potatoes.
7:51 Speaker 02 Mm hmm. So let's shift gears here back to nutrition for a minute. Potatoes get a bad rap, I would say, for being unhealthy. But can you set the record straight for us? Are potatoes nutritious?
8:05 Speaker 03 Absolutely, they're nutritious. Potatoes actually have quite a bit of a lot of the nutrients we need, like potassium and vitamin C and protein. So, you know, I used to know some guys that did long distance bike rides, and they would actually cook potatoes, little potatoes, and just put them in a bag on their back. And as they were riding these long distance rides, they would eat potatoes because it gave them. A lot of the nutrients they needed for those big expenditures of energy.
8:34 Speaker 02 What an amazing idea. I've never thought about that.
8:37 Speaker 03 I think a lot of the bad rap comes from how the potatoes are prepared. Cause I mean, you don't go to Thanksgiving dinner with just a potato and no butter or no sour cream or no bacon or
8:49 Speaker 02 Right, right.
8:50 Speaker 03 You don't, you don't eat french fries that are not cooked in oil.
8:53 Speaker 02 I have seen blue potatoes in the store, kind of a shocking sight. Are blue potatoes different nutritionally from white potatoes?
9:03 Speaker 03 Yes. So there's been some research done that's looked at the nutrition of colorful potatoes like that compared to a, a white potato. And they do have higher concentrations of, of, of nutrients, of carotenoids and other things that our bodies need. And so colored potatoes really do have a little bit more nutrients in them than just a regular white potato.
9:27 Speaker 02 Hmm. Okay. So as the potato expert, I have to ask you, do you have a favorite type of potato?
9:36 Speaker 03 You know, I, I really do like specialty potatoes or these, these colorful potatoes. Our program released one called Huckleberry Gold and it actually has a purple skin and a yellow flesh and it is just excellent for making mashed potatoes.
9:51 Speaker 02 That sounds beautiful. Do you have a least favorite type of potato that we should be avoiding?
9:57 Speaker 03 Well, given, given my employment, I don't know if I should be bad mouthing the potatoes that I don't like so much, but there, there are some that I wish that we could replace because they're, they're not efficient to grow. They take a lot of nutrients and water and any little tiny hiccup will, you know, give you a, a bad yield or bad quality in the end of the season.
10:18 Speaker 02 Okay. So one little safety question to end us off here. Let's just say that I forgot about a potato in my pantry and it has turned green. Is it safe for me to eat that green potato?
10:33 Speaker 03 You know, that green usually doesn't go very deep into the potato. So if you peeled it past the green, you'd probably be just fine. The potato plant does produce a toxic chemical called solanine. That's usually pretty much concentrated in the leaves and the stems or the parts that we don't eat. But potatoes that have been left in the light can develop higher concentrations of that chemical. So I wouldn't recommend eating a green potato. I would probably peel that off first, but you'd probably have to eat a lot of them to get sick.
11:05 Speaker 02 Good to know, and thank you so much for being here, Dr. Spear.
11:10 Speaker 03 Yeah, thank you very much.
11:11 Speaker 02 Dr. Rhett Spear, Assistant Professor in the Plant Sciences Department at the University of Idaho, based in Aberdeen, Idaho.
11:21 Speaker 00 After the break, the food science being done to make plant-based meats taste like the real thing. We'll be right back.
11:33 Speaker 04 I'm Kevin Roos. And I'm Casey Newton. And together, we've been tech journalists for decades. Now, we're your hosts of Machine Gods, a new podcast from NPR that makes sense of what AI means for your work, your life, and all of our futures. Twice a week, we'll be exploring the biggest moves in tech and give you unmatched access to the real titans of industry. Listen to Machine Gods from NPR on the NPR app or wherever you get your podcasts.
12:02 Speaker 02 If you've been or been with a vegan or a vegetarian at a Thanksgiving meal, it's possible that you've run into the famous Tofurkey roast around plant-based imitation meat. You can find plant-based meats in a lot of different forms these days, like sausages, deli meats, and faux chicken nuggets. But there are still a lot of challenges to getting plant-based meat to mimic their real counterparts. A big challenge for food scientists is marbling, which helps give real meat its, well, meaty texture. My guest today is working on this very question. Dr. David Julian McClements, distinguished professor in food science at the University of Massachusetts Amherst. Welcome to Science Friday. Thanks for being here.
12:46 Speaker 01 Yeah, great. Thanks for having me.
12:47 Speaker 02 So what is marbling in meat scientifically?
12:51 Speaker 01 Yeah, so marbling is when you look at meat, you see these white regions and red regions. And the whitish regions are the regions full of fat, which is called adipose tissue. So you have these fat cells. They have a whitish appearance because they scatter light quite strongly and then they're surrounded by these red regions, which are the sort of fibrous protein-rich regions.
13:12 Speaker 02 So for anybody who has had plant-based meat, they'll know that it can be a monotextural experience. You don't have those pockets of fat and those other irregularities because the fake meat is processed to be that way. So how are you and your team looking at adding marbling to plant-based meat?
13:30 Speaker 01 Yeah, we have a few different ways that we're trying to do it. One way is we use 3D printing. So we like create these edible inks. So we have like an edible ink, which is a plant-based deposed tissue. And then we have another edible ink, which is like the lean tissue, which has got a natural red color, like an extract from beet in it. And then we'll use a 3D printer to print like the fat-rich regions and the protein-rich regions. So it looks something like real meat.
13:55 Speaker 02 So are you 3D printing just those elements? Or can you 3D print like a plant-based steak in its entirety?
14:03 Speaker 01 Yeah, I mean, I think my goal was always to do a plant-based bacon because I'm a vegetarian now and I haven't eaten English bacon for years and years. And it was one of the things I really missed. So I've been trying to get my students to do like a nice plant-based bacon kind of product. But you could also do like a roast beef or something like that as well, or, you know, a turkey kind of product for Thanksgiving.
14:23 Speaker 02 Right. What are the biggest challenges with marbling and adding this texture to plant-based meat?
14:30 Speaker 01 Yeah, because I think if you look at real meat at a structural level, it's incredibly complicated. I think we're so used to these materials every day, we don't realize what's actually going on at the molecular level and the structural level. So I think trying to mimic the structural architecture of meat, these little tiny micrometer-sized fat cells, which are coated by phospholens and proteins, so trying to mimic that with plant-based ingredients and get the same sort of texture and taste and appearance and nutritional properties is really, really challenging.
15:00 Speaker 02 What have been the most successful strategies that you have found in your career?
15:05 Speaker 01 Yeah, do we use something called emulsion gels? They've got fat droplets in them, these very small little beads, which are full of fat and we coat them with our proteins. And then inside them, we might put things like coconut oil, which will give like the solidity that you would normally get from the sort of large you would get in beef or other kinds of products. So we can make a product that looks and feels a lot like real depot tissue. But the problem with using coconut oil is it's full of saturated fat. And saturated fat is not good for your health, especially like heart health.
15:38 Speaker 02 Right.
15:38 Speaker 01 So we're trying to find alternatives for doing that to make it healthier as well.
15:42 Speaker 02 I would imagine another challenge is, you know, when you're turning a raw steak into a cooked steak, when you cook that item, there's different chemistry going on with that fat compared to the other parts of the meat. Is that something that you have been working on, on addressing for plant-based meat?
16:00 Speaker 01 Yeah, if you look at real beef, at room temperature, it's quite hard. Then when you heat it, all the fat crystals will melt and it'll become softer. And that's sort of melting in your mouth characteristic can be really important for certain types of food products. So we're trying to mimic that behavior where it behaves in one way at room temperature. When you heat it, it behaves very differently. So it releases oil and then that lubricates your mouth and gives you a nice sort of juicy mouth feel when you're consuming the product.
16:27 Speaker 02 How close do you think we are to having an effectively marbled piece of plant-based meat available for purchase?
16:35 Speaker 01 We're getting closer. I don't think we're nowhere near there yet. And I think we still need to do a lot of science before we get there. But I think we're getting better and better at doing it. And there are some reasonably good products on the market now.
16:46 Speaker 02 So not next year's Thanksgiving, but maybe a decade from now?
16:51 Speaker 01 Possibly, possibly a little bit shorter than that.
16:54 Speaker 02 Besides marbling, what other textural challenges to plant-based meat are you working on?
16:59 Speaker 01 Yeah, I think, you know, the marbling is to do with the fat part of the meat. But it's also the challenges to do with the lean part of the meat. And the lean part of the meat is what gives it like chewiness in the mouth. And I think if you've eaten it a lot, so these plant-based products, you know, like Impossible Burger or Beyond Meat Burger, they often are quite mushy when you bite into them. So they break down too easily in your mouth. So we're trying to make a product that would be more simulate like a real meat product and how that behaves or retains some of its texture in the mouth when you're chewing it. And again, that's really challenging to do because plant-based ingredients are very, very different from animal-based ingredients. So you need to use all these structural architecture methods to try and do that.
17:39 Speaker 02 I have heard this argument a lot in my own time exploring meat alternatives, where people say, why are you going for these ultra-processed fake meats when you can just eat lentils or beans or get your protein elsewhere? And I'm sure you've heard that a lot as well. So as a food scientist, why focus on making plant-based meats better?
17:59 Speaker 01 Yeah, I think the ultimate objective is to address sort of greenhouse gas emissions and sustainability and biodiversity. So I think, you know, the meat and livestock production is a really big contributor to all those adverse effects on our environment. So we want to create this new generation of foods that are going to be better for our environment and also better for our health. But if you look at consumers, 95% of consumers are meat eaters. So we really need to target the meat eaters if we want to have a big environmental and sustainability impact. So we need to make a product that people don't need to make any lifestyle changes. They can just go to the supermarket, buy a product, it looks the same, it tastes the same, it cooks the same. You don't have to make any changes, but you're having a big impact on the environment.
18:44 Speaker 02 Well, that's all the time that we have for today. I'd like to thank my guest, Dr. David Julian McClements, distinguished professor in food science at the University of Massachusetts Amherst. Thanks so much for being here.
18:55 Speaker 01 Fantastic. Thanks for having me.
18:58 Speaker 00 And that's all the time we have for now. Lots of folks helped make the show happen, including
19:02 Speaker 05 Emma Gomez.
19:03 Speaker 02 Sandy Roberts.
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19:07 Speaker 00 Tomorrow, we start our celebration of 33 years on the air. Over the next few days, you'll hear some of the stories listeners picked as favorites from our archive. And we'll start things off tomorrow with a 2018 conversation with actor and science communicator Alan Alda, talking about his own Parkinson's diagnosis. Thanks so much for listening. I'm Sci-Fry producer, Shoshana Buckspow. We'll catch you next time.
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