Synsepalum dulcificum and citrus
A year and a half ago, my aunt in Taiwan gave me a little dried fruit to taste. After chewing on the pulp, I ate some sour citrus fruit, and to my surprise, it converted sour to sweet! I've been telling friends about it since then, but had never found a mainstream article about the fruit hitting the States until now. The taste twist is due to a protein called miraculin, which is sort of a lame name. People are calling the experience "favor tripping."
The miracle fruit, Synsepalum dulcificum, is native to West Africa and has been known to Westerners since the 18th century. The cause of the reaction is a protein called miraculin, which binds with the taste buds and acts as a sweetness inducer when it comes in contact with acids, according to a scientist who has studied the fruit...
Full article is at New York Times: A Tiny Fruit That Tricks the Tongue
I also just noticed that the NYT website overrides double clicks and turns it into a site search for that term. Argh.