Tag Archives: Jeanne L. D. Osnas

Carrot top pesto through the looking glass

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

Maca: A Valentine’s Day Call for Comparative Biology

Sometimes food is medicine, and sometimes that medicine is an aphrodisiac. Such is the case with Andean staple maca. What elevates this high-altitude root vegetable above its cruciferous brethren?

The ancient Greek Hippocrates, the father of modern medicine, famously said: “Let food be your medicine.” For most of human history, categorizing an edible item as either food or medicine could prove difficult or impossible (Totelin 2015). Even in the current era of modern pharmaceuticals, food and medicine exist along a continuum (Johns 1996; Etkin 2006; Valussi & Scirè 2012; Leonti 2012; Totelin 2015). The traditional Andean food Maca (Lepidium meyenii; family Brassicaceae) can be placed squarely in the middle of that continuum. Herbal medicine markets outside of its native Peru have recently discovered maca and loudly and lucratively promote an aspect of maca’s medicinal reputation that has particular relevance on Valentine’s Day: an aphrodisiac that increases stamina and fertility (Balick & Lee 2002; Wang et al. 2007). Continue reading

Botany Lab of the Month, Presidential Inauguration Edition: Saffron

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

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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

Closing out the International Year of Pulses with Wishes for Whirled Peas (and a tour of edible legume diversity)

The United Nations declared 2016 the International Year of Pulses. What’s a pulse? It’s the dry mature seed of a large number of species in the legume family (Fabaceae): various beans, peas, soybean, chickpeas, lentils, peanuts and other groundnuts. 2016 is days from ending, so it’s high time I get up the Fabaceae diversity post I’ve been meaning to write all year long. This rounds out our year of legume coverage, which included Katherine’s posts on bean anatomy, peanuts, and green beans

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Christmas Lima beans (Phaseolus lunatus), soaking before cooking

One out of every 15 flowering plant (angiosperm) species is a legume, a member of the large plant family Fabaceae (Christenhusz and Byng 2016, LPWG 2013). Boasting around 19,500 species in 750-ish genera (LPWG 2013), the Fabaceae is the third-largest plant family in the world, trailing behind only the orchid (Orchidaceae: 27,800 species) and aster (Asteraceae: 25,040 species) families (Stevens 2016). By my count, people only use about 1% of legume species for food (my list of edible legume species is found here), but that small fraction of species is mighty. People eat and grow legumes because they are nutritional superstars, can be found in almost all terrestrial ecosystems around the world, and uniquely contribute to soil fertility in both wild and agricultural ecosystems. Continue reading

Virgin birth and hidden treasures: unwrapping some Christmas figs

Enjoy Jeanne and Katherine’s holiday take on figs and figgy pudding which will appear on December 19th in Advent Botany 2016. For a longer read, check out our original 2013 version.

Figs reach their peak in summertime, growing fat enough to split their skins under the hot sun. It’s nearly impossible to keep up with a bountiful tree, and many a neglected fig is extravagantly abandoned to the beetles.  

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Beetles gorge on a fig. Click to enlarge

But here we are, halfway around the calendar in dark and cold December, and we feel grateful for the figs we managed to set aside to dry. Their concentrated sweetness is balanced by a complex spicy flavor that makes dried figs exactly the right ingredient for dark and dense holiday desserts. As we mark another turn of the annual cycle from profligate to provident, what better way to celebrate than with a flaming mound of figgy pudding?

Well, except that the traditional holiday pudding contains no figs. More on that later, along with some old recipes. First, we’ll unwrap the fig itself to find out what’s inside. Continue reading

Winter mint

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

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

Sugar

This is our first of two contributions to Advent Botany 2015.

Sugar plums dance, sugar cookies disappear from Santa’s plate, and candied fruit cake gets passed around and around. Crystals of sugar twinkle in the Christmas lights, like scintillas of sunshine on the darkest day of the year. Katherine and Jeanne explore the many plant sources of sugar.

Even at a chemical level, there is something magical and awe-inspiring about sugar. Plants – those silent, gentle creatures – have the power to harness air and water and the fleeting light energy of a giant fireball 93 million miles away to forge sugar, among the most versatile compounds on earth, and a fuel used by essentially all living organisms.

Sugar naturally occurs in various chemical forms, all arising from fundamental 3-carbon components made inside the cells of green photosynthetic tissue. In plant cells, these components are exported from the chloroplasts into the cytoplasm, where they are exposed to a series of enzymes that remodel them into versions of glucose and fructose (both 6-carbon monosaccharides). One molecule of glucose and one of fructose are then joined to form sucrose (a 12-carbon disaccharide). See figure 1.

Sugars: glu, fru, and sucrose

Figure 1.

Sucrose is what we generally use as table sugar, and it is the form of sugar that a plant loads into its veins and transports throughout its body to be stored or used by growing tissues. When the sucrose reaches other organs, it may be broken back down into glucose and fructose, converted to other sugars, or combined into larger storage or structural molecules, depending on its use in that particular plant part and species. Since we extract sugar from various parts and species, the kind of sugar we harvest from a plant, and how much processing is required, obviously reflects the plant’s own use of the sugar. Continue reading

Throwback Thursday Thanksgiving feast

We’ve got several posts in the pipeline – and this year we are contributing to Advent Botany – but meanwhile, we bring you posts from the past to nerd-up your kitchen as you cook. Don’t forget, nothing deflects from an awkward personal revelation or a heated political conversation like a well-placed observation about plant morphology.

We wish you a happy, healthy Thanksgiving!

Continue reading

How giant pumpkins got so big: A Q&A with Jessica Savage

Biologist Jessica Savage answers a few of our questions about her research on the physiology behind giant pumpkin size.

In October 2014, a giant pumpkin grown by Beni Meier of Switzerland tipped the scales at 1056 kilograms (2323 pounds) and set a new world record for the heaviest pumpkin ever weighed. Modern competitive pumpkin growers have been imposing very strong selection on pumpkin size for decades. Pumpkin fruit size keeps climbing, and old records are broken every year or two (Savage et al. 2015).

Beni Meier with his 2014 record-winning 2323-pound pumpkin, presumably a specimen of the Atlantic Giant variety of Cucurbita maxima. Photo from here.

Continue reading

Taking advantage of convergent terpene evolution in the kitchen

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 (Piper nigrum) growing in Cambodia (photo by L. Osnas)

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).

Nutmeg seed showing brown seed coat folded within the ruminate endosperm

Nutmeg seed

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