Isomers are molecules that have the same chemical constituents in different physical arrangements. Some terpenoid isomers have very different aromas and are important food seasonings. A batch of carrot top pesto led to an exploration of intriguing terpenoid isomers in the mint, carrot, and lemon families.
“Oh, c’mon. Try it,” my husband admonished me with a smile. “If anyone would be excited about doing something with them, I should think it would be you.”
The “them” in question were carrot tops, the prolific pile of lacy greens still attached to the carrots we bought at the farmer’s market. I have known for years that carrot tops are edible and have occasionally investigated recipes for them, but that was the extent of my efforts to turn them into food. My excuse is that I harbored niggling doubts that carrot tops would taste good. Edible does not, after all, imply delicious. My husband had thrown down the gauntlet, though, by challenging my integrity as a vegetable enthusiast. I took a long look at the beautiful foliage on the counter.
“Fine,” I responded, sounding, I am sure, resigned. “I’ll make a pesto with them.”
Carrot tops, it turns out, make a superb pesto. I have the passion of a convert about it, and not just because my carrot tops will forevermore meet a fate suitable to their bountiful vitality. The pesto I made combined botanical ingredients from two plant families whose flavors highlight the fascinating chemistry of structural and stereo isomers. Continue reading
Posted in Flavor, herbs, Recipes, Uncategorized, Vegetables
Tagged ajwain, Apiaceae, carrot, carvacrol, carvone, Jeanne L. D. Osnas, Lamiaceae, oregano, pesto, recipe, terpene, thyme, thymol
If you like your spices gold-colored and expensive, find some fresh Crocus sativus flowers and grab ‘em by the…disproportionately large female reproductive organ. Small hands might work best, though it might turn your skin orange. Saffron is probably from the Middle East. If that bothers you, you may want to ban it from your spice shelves, however ill that bodes for the quality of your cabinet. After all, there is a stigma against that sort of thing.
The most expensive oversized reproductive organ in the world
A pile of dried saffron stigmas (“threads”). Photo from Wikipedia
You may know that saffron is the most expensive spice in the world. A Spanish farmer sold his crop of high quality saffron this year for four euros per gram, which is a ninth of today’s price of gold (36 euros per gram). Saffron is expensive because its production requires a huge amount of labor and land. Saffron production is labor- and land-intensive because saffron is a botanically unique food item that defies mechanical harvest and accounts for a miniscule proportion of the plant that bears it. The saffron threads sold as spice are the dried stigmas of the flowers of the saffron crocus (Crocus sativus, family Iridaceae). Recall that the stigma is the part of the flower’s female reproductive organs that catches pollen. Pollen travels from the stigma through the style into the flower’s ovary (collectively, the stigma, style, and ovary comprise the pistil). Continue reading
Posted in Botany Lab of the Month, Education, Flavor, herbs, Recipes, The basics
Tagged anatomy, carotenoid, climate change, Crocus sativus, flower, Jeanne L. D. Osnas, pollination, saffron, spice, stigma
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
The Cooks Illustrated recipe masters recently added nutmeg and orange zest to a pepper-crusted steak to replace two flavorful terpenes, pinene and limonene, lost from black pepper when simmered in oil. In doing so they take advantage of convergent evolution of terpenoids, the most diverse group of chemical products produced by plants. Nutmeg and orange zest, though, were hardly their only options.
The terpene swap
Black pepper growing (photo by L. Osnas)
To develop satisfying crunch, the Cooks Illustrated recipe for pepper-crusted beef tenderloin requires a prodigious quantity of coarsely ground black pepper (Piper nigrum; family Piperaceae). If applied to the meat raw, however, in the recipe authors’ view, this heap of pepper generates an unwelcome amount of spicy heat. To mellow it, the recipe authors recommend simmering the pepper in oil and straining it out of the oil before adding it to the dry rub. The hot oil draws out the alkaloid piperine, which makes black pepper taste hot, from the cracked black pepper fruits (peppercorns).
To their dismay, however, the recipe authors discovered that the hot oil also removes flavorful compounds from the cracked pepper, in particular the terpenes pinene and limonene. To rectify this flavor problem, the recipe authors added pinene-rich nutmeg (Myristica fragrans; Myristicaceae) and limonene-rich orange (Citrus x sinensis; Rutaceae) zest to the dry rub, along with the simmered black pepper. In doing so they take advantage of widespread and diverse array of terpenoids in the plant kingdom. Continue reading
Hummingbirds and ancient bees are responsible for the color and shape of nasturtium blossoms and have a unique view of them, explains Jeanne over salad.
Nasturtium flowers cut into tomato salad with parsley
Fall frost hasn’t yet claimed our nasturtiums (Tropaeolum majus; Tropaeolaceae family). The large, colorful blooms amidst the round leaves are still spilling over planting boxes. All parts of the plant are edible and boast spicy mustard oil glucosinolates, betraying the plant’s membership in the order Brassicales, along with the cruciferous vegetables and mustard in the Brassicaceae family, capers (Capparaceae), and papaya (Caricaceae; try the seeds, as suggested here). I’ve heard that the immature flower buds and immature seed pods can be pickled like capers, but I haven’t tried it yet. Mostly I use the flowers, throwing a few in a salad or chopping them coarsely with other herbs and stirring them into strained yogurt or butter to put on top of roasted vegetables or lentils. In addition to the mustardy kick, the sweet flower nectar adds to these dishes. Continue reading
Posted in Flavor, herbs, The basics, Uncategorized
Tagged Brassicales, flower, Jeanne L. D. Osnas, Nasturtium, nectar guide, pollination, symmetry, Tropaeolum, ultraviolet, zygomorphy
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
Tarragon is one of many Artemisia species with a storied past. Jeanne introduces you to her favorite genus.
If you love eating French food, and especially if you love cooking it, when you see a tarragon bush, inevitably you think of the French quartet fines herbes: fresh parsley, chives, tarragon and chervil. You may reminisce about a perfect (or broken) Béarnaise sauce. These days when I pass my tarragon plant I vow to actually use it, as we’ve neglected it this year. I also think of sagebrush. And absinthe, martinis, and Shakespeare. And weeds, malaria, and hippies. I attribute this motley mental association to tarragon’s membership in my favorite genus, Artemisia, a large group in the composite (sunflower) family, Asteraceae, with a rich history. Continue reading
Posted in herbs, Uncategorized
Tagged absinthe, Artemisia, Asteraceae, Béarnaise sauce, eudicot, herbal medicine, herbs, Jeanne L. D. Osnas, liqueur, phylogeny, tarragon, vermifuge, vermouth, wormwood
The three edibles from the order Dipsacales (mâche, elderberry and valerian) inadvertently make their way into Jeanne’s evening.
As I added some dried valerian (Valeriana officinalis) root to my bedtime tea mixture, I realized that in doing so I had inadvertently incorporated the only three common edibles from the order Dipsacales into my evening: elder, mâche, and valerian. These three make the Dipsacales a lonely but interesting and delicious branch of the asterid group of eudicots (see our phylogeny page for phylogenetic contextualization of the asterids):
Orders with edibles in the asterids, Dipsacales in red
Posted in Flavor, Fruit, herbs, Uncategorized
Tagged Dipsacales, elder, elder flower, elderberry, herbalism, Jeanne L. D. Osnas, mache, phylogeny, sambuca, Sambucus, syrup, valerian, Valeriana, Valerianaceae