淀粉与碘的颜色反应与还原糖含量的关系

On the Relationship between Color Reaction of Starch with I_2 and Content of Reducing Sugar

将糖的定性实验和定量实验相结合,我们测定了淀粉遇碘呈不同颜色反应阶段还原糖的含量,给出定性实验一个量化的结果。当底物淀粉浓度为2g L,加入α 淀粉酶为0.5u mL时,0～2.5min呈蓝色,2.5～5.5min呈紫色,5.5～13.5min呈红色,13.5min后呈无色。对应颜色变化点还原糖的分解比率分别为45%(蓝色→紫色),66%(紫色→红色),76%(红色→无色)。

An experiment was designed that combines both qualitative and quantitative experiment on sugar. The content of reducing sugar is measured when the different colors change during the reaction of starch with I_2, and a qualitative result corresponding to a quantitative experiment is reported. When the concentration of substrate starch is 2 g/L and that of α-amylase is 0.5u/mL, the solution shows blue, violet and red for the reaction time of 0～2.5 minu, 2.5～5.5min and 5.5～13.5 min respectively. Beyond 13.5 min, the solution turns to colorless. The decomposition rates of reducing sugar corresponding to the changing point of colors are 45% (blue to violet), 66%(violet to red) and 76%(red to colorless) respectively.