ACTIVITY AND STABILITY OF A NEW SWEET PROTEIN WITH TASTE-MODIFYING ACTION, CURCULIN

Curculin elicited a sweet taste. After the sweetness of curculin dimin ished, application of deionized water or an acid to the tongue induced a sweet taste. The maximum sweetness of curculin itself was equivalen t to the sweetness of 0.35 M sucrose. The maximum sweetness induced by 0.02 M citric acid or deionized water after curculin dissolved in a b uffer of pH 6.0 was held in mouth for 3 min was also equivalent to tha t of 0.35 M sucrose. The sweetness induced by deionized water was comp letely suppressed by the presence of 1 mM CaCl2 or MgCl2, while that i nduced by an acid was not suppressed by the presence of divalent catio ns. Based on these results, the mechanism of the taste-modifying activ ity was discussed. Stability of curculin was examined under various co nditions. The taste-modifying activity of curculin was unchanged when curculin was incubated at 50 degrees C for 1 h between pH 3 and 11.