In this Valentine’s Day edition, Katherine brings you a love song with a beet. Sweet and red, sort of heart-shaped, bearing rings, and definitely divisive – beets should be the unofficial vegetable of the holiday. And if you don’t feel like celebrating, then you can just sit alone and eat dirt.
Throughout two years of dating and our first six months of marriage, my husband and I had never discussed our feelings about beets. Then again, I had never made beets for him before. When I did, they were meant to bulk up a brimming vat of stew that would feed us every night for a week. In my husband’s version of the story, it lasted for three weeks. “I hope you like beets,” I announced that evening. “I may have added too many.”
Whether you love or hate beets, it is probably because they taste like dirt. Some people (my husband) can’t get over the flavor, and others can’t get enough of it. Some people experience beeturia, the appearance of bright red or hot pink urine after they eat red beets. Maybe this sight unsettles you. Or maybe you embrace the opportunity to track the transit of beet pigments through your body. You may admire their lovely rings and be inspired by the rich and brilliant colors that beets bring to salads. Or you might have picked up a lifelong aversion after too many canned pickled beets on a school lunch tray. Beets are a pretty polarizing vegetable. If you are among the haters, I’m going to do my best to turn the beet around for you.
Red and white beets
Why beets taste like dirt
Beets taste like dirt because they contain a compound called geosmin (meaning “dirt smell”). Geosmin is produced in abundance by several organisms that live in the soil, including fungi and some bacterial species in the genus Streptomyces. Humans are extremely sensitive to low concentrations of geosmin – so much so that we can smell it floating in the air after rain has stirred it up from the soil (Maher & Goldman, 2017). While people generally like that rain-fresh scent in the air, it’s less welcome elsewhere. For example, we perceive it as an off taste in water drawn from reservoirs with a lot of geosmin-producing cyanobacteria. In wines, geosmin contributes to cork taint. Continue reading
We are knee deep in peach season, and now is the time to gather the most diverse array of peaches you can find and unite them in jam. Katherine reports on some new discoveries about the genetics behind peach diversity and argues for minting up your peach jam.
Fresh peaches at their peak are fuzzy little miracles, glorious just as they are. But their buttery mouthfeel and dripping juice are lost when peaches are processed into jam and spread across rough toast. To compensate for textural changes, cooked peaches need a bit more adornment to heighten their flavor, even if it’s only a sprinkling of sugar. Normally I am not tempted to meddle with perfection by adding ginger or lavender or other flavors to peach jam. This year, however, as I plotted my jam strategy, the unusual juxtaposition of peach and mint found its way into my imagination over and over again, like the insistent echo of radio news playing in the background. Peach and mint, peach and mint, peach and mint – almost becoming a single word. To quiet the voice in my head I had to make some peach-mint jam. The odd combination turned out to be wonderful, and I’m now ready to submit the recipe to a candid world. As we will see below, it’s not without precedent. Mmmmmmpeachmint jam. Continue reading
Posted in Flavor, Fruit, Recipes, Uncategorized
Tagged evolution, flavor, fruit, genetics, nectarine, peach, recipe, Rosaceae, stonefruit
Winter is the season for citrus fruit, and January is the month for breaking out of old routines, so stop staring at your navel and learn about one of the weirder citrus varieties.
I’ll never forget the day one of my general botany students brought to class a Buddha’s hand citron, pulled from a tree right outside our classroom. I had only recently moved to northern California from Indiana, and I’d never seen anything like it: it was a monstrous mass of a dozen pointed twisted fingers splayed irregularly from a stout base. It had the firm heft and girth of a grapefruit and the unmistakable pebbled skin of a citrus fruit, so I wondered whether my student had found a grossly deformed grapefruit; but the oil in the peel smelled heavenly and not at all like a grapefruit. In class we cut through a big finger and found no juicy segments, just white citrus pith all the way through.
Immature Buddha’s hand on the tree
We eventually discovered that this fascinating fruit was a Buddha’s hand citron, Citrus medica variety sarcodactylis, meaning fleshy (sarco-) fingered (-dactyl) citron. Since that day many years ago I’ve become an unapologetic (if surreptitious) collector of the fruits from that same campus tree. The citrons do not drop from the tree on their own, yet I often find one or two lying nearby, probably torn off by a curious tourist or student and then abandoned. Obviously these fruits need a good home, and where better than the window sill in my office?
The first time I left one closed up in my office over a weekend, I opened the door on Monday morning to a waft of fruity floral aroma. It turns out that many people in China and India use the fruit to scent the air, although in west Asia and Europe the fleshy fingers are more often candied or used to flavor alcohol. I do both: the fruits make my office smell nice until they are fully yellow, and then I cook them.
It can be difficult or expensive to get your own hands on a fingered citron, but it’s easy to find a navel orange almost any time of the year. Fortunately, the patterns underlying the morphology of the fingered fruit can also be seen in an everyday navel orange. Between our photos of Buddha’s hands and your own navel orange, you should be able to follow along at home. Continue reading
This is our second of our two contributions to Advent Botany 2015. All the essays are great!
An early image of candy canes. From Wikipedia
The candy cane, that red- and white-striped hard candy imbued with peppermint oil, is a signature confection of the winter holidays. Peppermint has a long history of cultivation and both medicinal and culinary use. Infusions of the plant or its extract have been used for so many hundreds of years throughout Europe, North Africa and Western Asia that the early history of peppermint candies, including cane-shaped ones, is murky. Fortunately, the biology behind peppermint’s famous aroma is better known than the story of how it came to be a Christmas staple. Continue reading
Posted in Flavor, herbs, Uncategorized
Tagged aroma, candy cane, essential oil, flavor, fragrance, hybrid, Jeanne L. D. Osnas, Lamiaceae, Mentha, menthol, peppermint, receptor, spearmint, trichome, watermint
Why do so many rich tropical spices come from a few basal branches of the plant evolutionary tree? Katherine looks to their ancestral roots and finds a cake recipe for the mesozoic diet.
I think it was the Basal Angiosperm Cake that established our friendship a decade ago. Jeanne was the only student in my plant taxonomy class to appreciate the phylogeny-based cake I had made to mark the birthday of my co-teacher and colleague, Will Cornwell. Although I am genuinely fond of Will, I confess to using his birthday as an excuse to play around with ingredients derived from the lowermost branches of the flowering plant evolutionary tree. The recipe wasn’t even pure, since I abandoned the phylogenetically apt avocado for a crowd-pleasing evolutionary new-comer, chocolate. It also included flour and sugar, both monocots. As flawed as it was, the cake episode showed that Jeanne and I share some unusual intellectual character states – synapomorphies of the brain – and it launched our botanical collaborations.
Branches at the base of the angiosperm tree
The basal angiosperms (broadly construed) are the groups that diverged from the rest of the flowering plants (angiosperms) relatively early in their evolution. They give us the highly aromatic spices that inspired my cake – star anise, black pepper, bay leaf, cinnamon, and nutmeg. They also include water lilies and some familiar tree species – magnolias, tulip tree (Liriodendron), bay laurels, avocado, pawpaw (Asimina), and sassafras. Continue reading
Posted in Flavor, Recipes, The basics, Uncategorized
Tagged angiosperm, evolution, flavor, gluten free, pepper, phylogeny, recipe, spices
What is hairy, green, full of slime, and delicious covered in chocolate? It has to be okra, bhindi, gumbo, Abelmoschus esculentus, the edible parent of musk. Katherine explores okra structure, its kinship with chocolate, and especially its slippery nature. What’s not to like?
Okra flower with red fruit below
People often ask me about okra slime. Rarely do they ask for a good chocolate and okra recipe, which I will share unbidden. With or without the chocolate, though, okra is a tasty vegetable. The fruits can be fried, pickled, roasted, sautéed, and stewed. Young leaves are also edible, although I have never tried them and have no recipes. Okra fruits are low in calories and glycemic index and high in vitamin C, fiber, and minerals. The plant grows vigorously and quickly in hot climates, producing large and lovely cream colored flowers with red centers and imbricate petals. The bright green or rich burgundy young fruits are covered in soft hairs. When they are sliced raw, they look like intricate lace doilies. In stews, the slices look coarser, like wagon wheels. And yes, okra is slimy. And it is in the mallow family (Malvaceae), along with cotton, hibiscus, durian fruit, and chocolate. Continue reading
A batch of lemon balm-lemon verbena syrup reminds Jeanne of the multiple evolutionary origins of lemon flavor.
The citrus lemon itself is only one of many plant species that lends its namesake flavor or fragrance to our food and drinks. Lemon flavor primarily comes from a few terpenoid essential oils: citral (also called geranial, neral, or lemonal), linalool, limonene, geraniol, and citronellal. The production of one or more of these essential oils has independently evolved multiple times in species on widely separated branches of the plant phylogeny (see figure).
Phylogeny of plant taxonomic orders with edibles (click the tree to enlarge). Orders with species with lemony essential oils are highlighted in red. For a refresher on reading this phylogeny, please see our food plant tree of life page.
Posted in Flavor, herbs, Recipes
Tagged citronella, Citrus, essential oil, evolution, flavor, Jeanne L. D. Osnas, Lamiaceae, lemon, lemon balm, lemon verbena, lemongrass, syrup, terpenoid, trichome, Verbenaceae
Chili, black pepper, white pepper, and Sichuan pepper
Black pepper, pink peppercorns, chili pepper, Sichuan pepper – except for being “hot,” these spices have as little in common as Sergeant Pepper and Pepper Potts. Their homelands are scattered across the world, and they were spread through distinct trade routes. They are not closely related; they belong to families about as far apart as possible on the phylogenetic tree below. They even aim their heat at different sensory receptors in your mouth. Continue reading
Posted in Flavor, Fruit, Recipes, Uncategorized
Tagged Anacardiaceae, angiosperm, basal angiosperm, black pepper, capsaicin, capsicum, chili, chili pepper, convergence, eudicot, flavor, hot, hot sauce, Katherine Preston, magnoliid, pepper, phylogenetic relationships, piper, Piperaceae, Piperales, piperine, pungency, recipe, Rutaceae, Sapindales, Sichuan pepper, Solanaceae, Solanales, spice, spices, toxins, white pepper