If you have any foodie friends, you’ve probably heard of miracle fruit (Synsepalum dulcificum), a native West African berry that looks like a cranberry, but acts like a psychedelic for your taste buds.
Eat the miracle fruit on its own and it doesn’t taste like much of anything. But let the juices coat your mouth, then consume sour foods — like lemons, limes, goat cheese, beer, vinegar, pickles — and a remarkable thing happens: they all taste sweet.
“Beer tastes like sweet juice. Lemon tastes like sweet orange,” Keiko Abe of the University of Tokyo told Discovery News.
The fruit’s effect lasts for an hour, and like other trippy experiences, it’s more fun to do it in groups. So adventuresome eaters seek out “flavor tripping parties” during which people pop a berry, then gorge on all manner of sour foods. Guinness beer tastes like chocolate. Tabasco sauce tastes like “hot doughnut glaze,” as one flavor tripper was quoted as saying in this story in the New York Times.
This week, Abe and colleagues reported the key to miracle fruit’s magic. To figure it out, Abe’s research team used cell cultures to test human taste receptors at various pHs. According to Discovery News:
The key ingredient in the fruit, a protein known as miraculin, binds strongly to the sweet taste receptors on our tongues, Abe reported, but it does not activate the receptors at neutral pH.
When acid is introduced, the miraculin protein changes shape in such a way that it turns on the sweet receptors it is bound to, creating a sensation of ultra-sweet without affecting the other flavors in the food.
After the acidic food is swallowed, miraculin returns to the inactive shape, but it remains bound to the sweet receptor for up to an hour, ready to receive a new acid trigger. The strong binding explains the molecule’s lasting effect.
Abe said the sweet-making power of miraculin was stronger than nearly all other known sweeteners. Given that it’s calorie-free, of course there has been no shortage of interest in developing it into a commercially usable sweetener. Perhaps it will be in Japan, where the production of a purified miraculin extract is currently being sought. As for the U.S., however, a 1974 ruling by the Food and Drug Administration banned the sale of an extract.