The berry contains an active glycoprotein molecule, with some trailing carbohydrate chains, called miraculin. When the fleshy part of the fruit is eaten, this molecule binds to the tongue's taste buds, causing bitter and sour foods to taste sweet. While the exact cause for this change is unknown, one hypothesis is that the effect may be caused if miraculin works by distorting the shape of sweetness receptors "so that they become responsive to acids, instead of sugar and other sweet things." This effect lasts between thirty minutes and two hours.
For a time in the 1970s, US dieters could purchase a pill form of miraculin. It was at this time that the idea of the "miraculin party" was conceived. Recently, this phenomenon has enjoyed some revival in Bacchanalian-like food tasting events, referred to as "flavor tripping parties" by some. The tasters consume sour and bitter foods, such as lemons, radishes, and beer, to experience the taste changes that occur. A blog dedicated to the phenomenon of "flavor tripping" describes the miracle fruit "like a candy Willy Wonka would have invented."
Attempts have been made to create an artificial sweetener from the fruit, with an idea of developing this for diabetics. At present, at least one company is pursuing the development of a purified version of the protein with the hopes of gaining approval.
Fruit cultivators also report a small demand from cancer patients since the fruit allegedly counteracts a metallic taste in the mouth that may be one of the many side effects of chemotherapy. However, there has been no scientific research conducted to support this claim.
In 2006, researchers at the University of Tsukuba genetically engineered lettuce to produce large amounts of miraculin. The scientists' crops resulted in 40 micrograms of miraculin per gram of lettuce leaves, which was considered a large amount. Two grams of lettuce leaves produced roughly the same amount of miraculin as in one miracle fruit berry. The researchers said others had unsuccessfully utilized bacteria, yeast and tobacco plants.
Miracle fruit is available as freeze dried granules or in tablets - this form has a longer shelf life than fresh fruit. Tablets are made from compressed freeze dried fruit which causes the texture to be clearly visible even in tablet form.
The effect of Miracle fruit is made possible by contact with the tongue, not through digestion. For this reason, tablets must be allowed to dissolve in the mouth. The most pronounced effect can be achieved by coating the entire tongue in a paste of Miracle fruit for up to 30 seconds.
The tablets are currently very difficult to get outside of Asia, where they are popular among diabetics and dieters. However, in many countries they can be purchased on the Internet.