The miracle fruit, or miracle berry plant (Synsepalum dulcificum), produces berries that, when eaten, cause sour foods (such as lemons and limes) subsequently consumed to taste sweet.
The berry, which contains active polyphenols, The berry itself has a low sugar content and a mildly sweet tang.
It 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 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 15-60 minutes.
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