Sugar affects the freezing point of foods. The higher the concentration of sugar, the lower the freezing point. A low freezing point is important in ice cream and frozen desserts. It reduces the risk of large crystals of ice forming. Small ice crystals have a positive effect on the sensation in the mouth, and hence on the taste.
The freezing point depression is due to the number of molecules per unit of weight. This means that glucose, fructose and invert sugar are more effective than ordinary sugar in reducing the freezing point of foods.