This must be a true holiday treat: Eat miraculin for Christmas and everything sour will turn sweet! Reading Joseph Mallozzi’s blog post on his visit to Jeff Ramsey’s Tapas Molecular Bar in Tokyo, I became aware of the miracle fruit. For one of the dishes, the guests are asked to eat the flesh of the miracle fruit and keept in in their mouth for one full minute. Following this the guests are given grapefruit which then tastes sweet! The miracle fruit is not sweet by itself, but the tongue will perceive sour foods as sweet for one half to two hours after it has been treated with the miracle fruit.
The active compound is a glycoprotein named miraculin. It consists of 191 amino acids linked together (the sequence can be found here). From what I have found, it is not known how miraculin interacts with the taste receptors on the tongue.
Unfortunately it seems to be quite difficult to get hold of the miracle fruit as they perish quickly. A couple of years ago however, a Japanese company developed a technique to freeze dry the fruit and desserts made with the fruit are served at the Miracle Fruits Cafe. Apparently, miraculin is available in tablet form in Japan (more info in Japanese here).
This year, japanese researchers were able to transfer a synthetic gene, encoding miraculin, into lettuce. The miraculin produced by the transgene lettuce had the same taste modifying properties as the miraculin found in the miracle fruit. But since it appears the FDA has turned down an application for marketing miracle fruit, it doesn’t seem likely for neither the miracle fruit nor the transgene lettuce to reach the super market next door… But I still hope Santa will bring me some miraculin for Christmas!