Curculin and Miraculin

Curculin is a sweet protein (/sac, g (6.8) = 550) of known sequence (Table 8.6). It occurs in the fruit of Curculigo latifolia. The sweet taste induced by this protein disappears after a few minutes, only to reappear with the same intensity on rinsing with water. It is assumed that Ca and/or Mg ions in the saliva suppress the sweet taste. Rinsing with citric acid (0.02mol/l) considerably enhances the impression of sweetness (/sac, g(12) = 970). Thus, like miraculin, curculin acts as a taste modifier. 

Miraculin is a glycoprotein present in the fruit of Synsepalum dulcificum (a tropical fruit known as miracle berry). Although it is tasteless, it has the property of giving sour solutions a sweet taste and therefore it is called a taste modifier. Thus, lemon juice seems sweet when the mouth is first rinsed with a solution of miraculin. The molecular weight of this taste modifier is 42-44 kdal. 

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Table 2. Comparison of Thaumatin, Monellin, Mabinlin, Pentadin, Brazzein, Curculin and Miraculin... 

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