I haven't posted here in a while. I'm going to try posting something blank and building it up over time, like a wiki article. It surely won't ever get posted if I write it in a text editor. So here we go: Space Food. Part 3/3.
Botanical Manufacturing Of Space Food:
:: Plant Protein
A few plants are complete proteins, meaning they contain adequate concentrations of the nine essential amino acids for adults such that you can meet your amino acid requirements by eating normally-sized portions of them. The seeds of amaranth, buckwheat, and quinoa are all complete proteins. The three of them are all classified as pseudo-cereals, because while they are culinary grains, the plants are not grasses botanically. Amaranth was a staple crop of the Aztecs, who called it huauhtli. The Spanish banned its cultivation, but like spirulina, it survived uncultivated in the wild. It won't grow well in cold dark climates like Mars, which is sad. I think it would be beautiful if the Aztec foods all but destroyed by the expeditions of Cortes and his ilk, now finally restored, just happened to be the ideal food sources for expeditions of Martian astronauts - like we'd be getting to Mars precisely in spite of Cortes. Quinoa is in the same family as amaranth and it is a little more cold-hardy. It was cultivated in Peru, and was a staple crop of the Inca and the Tiwanaku before them. And the Inca culture was also destroyed by the Spanish conquistadores. So fuck you, Cortes, we're eating quinoa on Mars. We're eating quinoa on the New World. I don't even like quinoa, but I am highly motivated in this regard.
Among legumes, soy is also a complete protein. I see lots of people online shouting about the health effects of phytoestrogen isoflavones in soy. I have no earthly idea if it's a real health concern. Until I know, I would be reluctant to design a plant-based space diet with soy as its main protein source. For other plants, I've seen seeds of pumpkin, hemp, and chia sometimes listed as complete proteins on websites with dietary advice for vegans. I'll look into them in the oil crop section.
True cereal grains are all deficient in one or more essential amino acids, to my knowledge. Wheat gluten (also known as seitan since 1961 when we started molding it into meat shapes) is only deficient in lysine. The true cereals also have a lower protein content than the pseudocereal grains, by about half. Rice is deficient in three or four amino acids, depending on the variety, particularly lysine, methionine, and phenylalanine. There's a cool paper about engineering rice to improve its lysine content, but that still leaves us pretty far behind wheat, if you're looking at cereal grains.
"What about potatoes, James?! We want to grow potatoes in poop, like Matt Damon!" Potatoes have very little protein, which is too bad because the amino acids are present in good ratios. You'd have to eat several kilograms of potatoes per day to get your requisite amino acids. The leucine is a little shy of what we'd like, but it would still be adequate.
:: Plant Carbohydrates
Carbs come for free with plants. For example, the carbohydrate content of amaranth is five times its protein content by mass, and amaranth is high in protein for a grain. You also get carbs with non-starchy vegetables - ex. lettuce contains more carbohydrates by weight than it does protein, fat, or fiber. And since carbohydrates aren't even essential, I think that's enough said. If you have a sweet tooth and are looking for a sugar crop, I wouldn't recommend sugar beets. They're not nearly as cold tolerant as their sister the beetroot. What I'm tempted to suggest instead, is to take some indigestible plant material with lots of starch or cellulose and then perform acid hydrolysis by heating it to about 200 C with dilute hydrochloric acid. That will give you delicious glucose syrup with some remaining acid that can be neutralized with baking soda, forming a little table salt. I wonder if that's why all the glucose syrup in the store comes with salt. If you like, the syrup can then be dehydrated into glucose powder.
Hm. I have ready access to cellulose and hydrochloric acid. Maybe I should try making paper into glucose. I could find out just how difficult it really is.
Alternatively, you could grow something sweet. Maybe grapes? I've always had good luck growing grapes in a cold climate. High yield, moderately long fruiting season, grows like a weed. Among cold-tolerant fruit crops, I think they'd definitely be easier to grow in a space habitat than say apples or raspberries. And they're sweeter than gooseberries and less prone to spoilage than strawberries. Good balance.
:: Plant Vitamins
The vitamins are A, C, D, E, K, B1, B2, B3, B5, B6, B7, B9, and B12. And choline. How many of these can we get from plants? Is there a single plant or a pair of plants that gives us all of them? Well, no. B12 is only made by bacteria and human chemists. But how about the rest of them? Still no; plants don't make vitamin D; fungi make the D2 vitamer, and animals make D3. But all the rest of them? Kind of, yes!
The first pairing I examined was quinoa for protein and spinach to cover for the remaining vitamins. Piecing together vitamin profiles for each plant from lots of sites and comparing them to recommended intake values, the combination was pretty close, but deficient in vitamins D, B3, B5, and B7, ignoring B12 for a moment. But all of those are in mushrooms! It looks to me that if every day you're eating 5 cups each of cooked quinoa, raw spinach, and button mushrooms, then you're getting all of your vitamins (and choline) except for B12. Something on the menu should to be raw, because vitamin C is degraded by cooking, and also some of the B vitamins but less so.
I'm going to recheck the numbers with different sources, but I'm pretty happy with that. It's a normal meal (for vegetarians at least) made of ingredients that I have prior reasons to expect would contain different vitamins in significant amounts. And I know that spinach and mushrooms aren't too hard to grow, even in cold dark places like the North American Northwoods. If quinoa is easy to grow, then that is a diet suitable for highly motivated individuals in space, at least in terms of vitamins. It's actually still low in terms of calories (because spinach and mushrooms provide very few) and a little low on protein (another 20 grams daily wouldn't hurt). You can supplement a little chlorella protein and get your B12 in the process, but this plant diet still needs a little something more.
"Does it need some delicious orange-flavored glycerol Tang for calories?" Not a bad idea, but I think we should look for a way to make the plant diet more adequate by using plants (or fungi or seaweed). Something that's stupid easy to grow. I'll keep thinking. Two fatty acids are also essential, and adding a little vegetable oil could help with calories. For protein, maybe just add some more quinoa. Or a legume.
I got the idea of a two-plant diet from a NASA research paper advocating wheat and soy as the main plant components of a space diet, "Feasibility Of Producing A Range Of Food Products From A Limited Range Of Undifferentiated Major Food Components", (Karel et al, 1984). It's quite clever, actually. Wheat is a carbohydrate and a protein. Soy is a protein and an oil crop. You can get lots of different foods from them, like bread, porridge, pasta, beer, whisky, edamame, tofu, tempeh, soybean oil, and soy sauce. If phytoestrogen isoflavones in soy aren't an issue for human health, it looks at first glance like a pretty good diet. It's higher in calories than quinoa + spinach, because soy has lots of calories while spinach hardly provides any.
How does the diet of wheat and soy do in terms of vitamins? Not great. Soy is pretty good for vitamins. It's deficient in D and B12 like all plants, and also A, C, E, B3, and B5, but the rest are covered. Wheat is atrocious for vitamins, even whole wheat. It helps a little bit with the B3 and B5, but not enough. But we can get D, B3, and B5 from mushrooms like before, so who even cares. We're still short of vitamins A, C, and E. Wheat germ is actually high in vitamin E, but milling it to make flour causes the vitamin E to be destroyed by oxidation. If there's a way to get wheat germ oil and wheat flour simultaneously, that could have merit. But we're still lacking vitamins A and C. For vitamin coverage, I think we should just forget the wheat. Soy and broccoli, supplemented with mushrooms and chlorella, would be way better, for vitamins at least. Kale and cabbage are the same species of as broccoli, and I think they're a little more cold-tolerant. If those varieties have similar vitamin profiles, then they might be better than broccoli for space. But the temperature difference also isn't that big. I'm sticking with broccoli for now. Also, google isn't backing me up on this, but I thought it was a common cultural joke that we'll one day grow broccoli on the moon under a big glass dome. In my mind, broccoli is a traditional space food, like Tang, freeze-dried ice cream, Gagarin's meat puree in a toothpaste tube, Aldrin's Presbyterian communion, Watney's potatoes grown in poop, and Picard's tea, Earl Grey, hot. It was probably just mentioned in some throwaway comment on a television sitcom I saw as a kid, but Moon Broccoli is real to me.
So for vitamins, a good set of plants to take to space might be quinoa, spinach, soy, and broccoli. That gives you some redundancy. Including another grain like buckwheat or regular wheat wouldn't hurt for carbs and protein, or for use in making a wider variety of traditional food items.
Alongside nutrition, plant productivity matters a lot for space diets, and to this end, a NASA funded team led by Bruce Bugbee developed a fast growing, high-yield dwarf cultivar of wheat called "Apogee" back in 1996. It honestly sounds pretty cool. Gotta keep an eye on Bruce. He's up to good things.
:: Essential Fatty Acids And Oil Crops
Soy is an oil crop, but it's not a great one. It has both of the fatty acids that are essential for adults (linoleic acid (LA) and alpha-linolenic acid (ALA)), but about seven times more of the first one, and you want a ratio somewhere between 1:1 and 5:1, not 7:1. Adults can still live on 7:1, but it's not ideal.
So what else can we bring? We can totally throw a couple more plants in the mix. This is still easier than bringing all the chemical manufacturing equipment.
Flaxseed oil is high in ALA. In fact, it has more ALA than LA (about 4 times as much) and it's the only oil crop I know of that reverses the ratio. You'd have to mix some soybean oil with your flax oil to get a healthy ratio. Flaxseed is also called linseed oil. Besides its oil content, flaxseed is mostly indigestible fiber, which isn't necessarily what you want when making space food. However the plant fibers can be used to make linen cloth, and the oil can be used to waterproof basically any kind of cloth. The oil can also be made into a sealant putty which is also a component of resinous floor coverings (linoleum). Flax is pretty cool. It wouldn't be the worst thing to bring it to Mars even if the seeds aren't very edible. No plants have the fatty acids AA or DHA that infants need, particularly babies born preterm, so it's a good thing we can make them by other means. I'm not sure about the other conditionally essential fatty acids. Flaxseed oil doesn't have EPA. I don't know about conditionally essential GLA or DPA. But some mix of soy and flax oil is probably alright for most adults.
What other oil crops might work for us out in space? I think peanuts and cotton would be poor choices for an oil crop in space or on Mars because they need long warm growing seasons and full sun. Corn oil has an even high ratio of LA to ALA than soybean. Forget corn. Canola?
Canola is good for ALA. It has a 2:1 ratio of LA to ALA. The name "canola" refers to oil from seeds of any of three different species of plants in the genus Brassica, namely B. rapa, B, napus, and B. juncea. Of the three, Brassica rapa is the one I know best. Cultivars of rapa have famous names like turnip, napa cabbage, and bok choi. The subspecies of B. rapa that's used as an oil crop rather than a vegetable is called field mustard, among several less fortunate names like turnip rape. I think the Brassica species most cultivated for oil is B. napa napa. I've never grown any canola myself, but it grows on the Canada Prairies, where the lowest temperatures recorded in a year are usually about -34 C. That's a good sign for the feasibility of growing canola in a space habitat. And you can probably eat the leaves and roots of the subspecies bred for oil production, just as you eat the roots and leaves of the turnip and napa cabbage subspecies. So that's great, right? Good ratio of ALA, cold-hardy, almost surely edible from root to flower. What more do we need? EPA, GLA, and DPA, maybe.
There are some other oil crops I want to look at:
...
:: Botanical Recycling, Essential Chemical Elements, And Hyperaccumulator Plants
:: Productivity And Ease Of Growing
Cold-hardiness and shade-tolerance:
Cosmic radiation:
Indoor farming, vertical farming, grow light spectra, and growing seasons:
Soil-based agriculture, hydroponics, and aeroponics:
---
The end.
Goodnight, friends.
--
Several months later: The plants I suggested provided essential nutrients and calories and were fairly fairly cold-hardy. What if you optimize for cold-hardiness in selection of edible plants? Then you could have a second greenhouse that required less energy for heating.
* The arctic willow (Salix arctica) is a small creeping artic plant, parts of which are apparently edible, sweet, and nutritious.
* Dwarf shrubs in the genus Arctostaphylos are commonly called bearberries (or kinnickinnick). They grow in the arctic and their berries that are fairly edible, but maybe don't eat too many.
* The leaves of the arctic Saxifraga oppositifolia (purple saxifrage) are eaten by humans.
* The roots of alpine sweetvetch (Hedysarum alpinum) are edible and a significant food-source for the Iñupiat people of Alaska.
* Common Cottongrass (Eriophorum angustifolium ) is not the same as textile cotton, but related. It grows in the arctic and its seeds, stems, leaves, and roots are all edible.
* Plants in the genus Claytonia are called Spring Beauty and the taxonomists aren't sure how many species, but some species of Claytonia grow in the Arctic (C. arctica or C. sarmentosa or C. scammaniana or C. tuberosa or C. ...). The roots, leaves, and flowers are all edible.
* Dulse (Palmaria palmata aka P. mollis) is a widely eaten red alga that grows wonderfully in artic waters. I don't think growing macroalgae in water tanks makes sense on space ships (because water is heavy and vital and you need reclaim it efficiently) but on a terrestrial planet with ice, like Mars, maybe macro-algae tanks are a good idea. There are other good edible arctic macroalgae/seeweeds like the brown seaweeds in the genus Fucus (called wrack) and others in the genera Laminaria, Saccharina, and Alaria (varieties of kelp).
* Rumex arcticus (Arctic dock) has edible leaves.
* Oxyria digyna (Alpine sorrel) grows in the Arctic, and its leaves are somewhat edible, but not much because of the oxalic acid, but cooking helps to degrade the oxalic acid, but it also degrades vitamins.
* Sea sandwort (Honckenya peploides) can grow in arctic regions, but only on sandy beaches. The seeds, leaves, and shoots are all edible.
* Seacoast angelica (Angelica lucida) also grows on arctic coasts. All of its parts are apparently edible.
* Beach Lovage or Scots Lovage (Ligusticum scoticum) is edible and can grow in arctic regions.
* Parry's wallflower or Wild Cabbage (Parrya nudicaulis) has edile leaves and roots.
* The Arctic sweet coltsfoot or Arctic butterbur (Petasites frigidus) is related to but distinct from eastern coltsfoot (Tussilago farfara). It has edible leaves, flowers, leaf stalks, and flowers stems.
* The common cranberry (Oxycoccus palustris) and the Small Cranberry (Oxycoccus microcarpus ) of course have edible fruits and they grow in the well in the Arctic.
* Fireweed (Chamaenerion) is edible and cold hardy. I think only one species lives in the arctic, but I'm not sure which. But others live on similarly cold mountains.
* Of the woolly lousewort (Pedicularis lanata), the roots, flowers, leaves and stems are all edible. Eat the whole thing.
* I've heard differing reports about the edibility of milk vetches (Astragalus umbellatus and Astragalus frigidus). Maybe the roots. Maybe the unripe seed pods. Maybe just poisonous. Probably best to try something else.
And here are a bunch more edible arctic berries:
* Empetrum nigrum (Crowberry)
* Rubus arcticus (Nagoonberry)
* Rubus chamaemorus (Cloudberry, Salmonberry)
* Vaccinium uliginosum (Bog Bilberry)
* Vaccinium vitis-idaea (Lingonberry)
I've got some guesses about which of the plants above would do better on mars, but why not just bring a bunch of seeds and find out? There's only like 20 different plants (also some macro-alga). You can fit that experiment in like four square meters of floor space. Two or three more greenhouses that size and you've got an arctic salad bar for your crew.
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