As snow blankets BBG’s outdoor collections, a world of wonder flourishes in the Steinhardt Conservatory below. During your next visit, try to spot one of these unusual fruits in the Tropical Pavilion. No snacking, please!
Synsepalum dulcificum
Synsepalum dulcificum (miracle fruit), an evergreen shrub, has a remarkable ability: Its small, red berries make sour food taste sweet. Native to the tropical regions of West Africa, Synsepalum dulcificum has been used for centuries to make foods and drinks more palatable.
The chemical cause for the effect was unknown until 1968 when researchers identified and isolated the cause for the plant’s unique property—a glycoprotein they aptly called “miraculin.”
Miraculin works by binding itself to—but not activating—sweet-sensing taste receptors in the tongue. When subjected to sustenance with pH values between approximately 3.0 and 6.0, the miraculin causes these receptors to activate. Thus, eating miracle fruit doesn’t eliminate other food and drinks’ sourness. Rather, it layers sweetness atop the acidity.
Vanilla planifolia
The source of the world’s favorite ice cream flavor is a vining orchid fruiting this winter at BBG. When cultivated outside of its pollinators’ native range, the flowers of Vanilla planifolia (vanilla)—each of which blooms for one day only—must be pollinated by hand to bear fruit.
At BBG, this means Tropical Pavilion gardener Kate Murphy carefully and precisely connects “the flower’s male bit to the female bit”—but the bits are delicate and the maneuver requires precision and dexterity. The method was established in 1841 by Edmond Albius—an enslaved 12-year-old boy on the Island of Réunion—and is employed to pollinate virtually all the world’s vanilla today.
After pollination, the flower drops off and green pods emerge that turn yellow and elongate until they resemble skinny bananas. The pods hold thousands of tiny black seeds and take eight to ten months to fully mature. Once harvested, it takes another few months of curing to develop vanilla’s characteristic flavor.
Averrhoa carambola
Averrhoa carambola (carambola), commonly called star fruit, is also currently bearing fruit in the Tropical Pavilion, just in time for Lunar New Year. The small, evergreen tree is a member of the Oxalidaceae, or wood-sorrels family, and has been cultivated in tropical Southeast Asia for centuries, though it is now extinct in the wild.
Carambola bears fruit the size of small pears, with mature trees producing more than 250 pounds per year in optimal conditions. Typically, each fruit features five prominent ridges, so slices of the fruit resemble five-pointed stars. Tasting sweet and sour, carambolas have low calorie content and are high in fiber and vitamin C.
