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
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
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