Final answer:
Confectioner's sugar, a mixture of finely ground granulated sugar (sucrose) and cornstarch, is used for icings and dusting on sweets. Sucrose, the main ingredient, is a disaccharide made of glucose and fructose, while cornstarch helps to prevent clumping.
Step-by-step explanation:
The sugar that is a mixture of pulverized granulated sugar and cornstarch is commonly known as confectioner's sugar, also referred to as powdered sugar or icing sugar. Granulated sugar, when ground to a fine powder and mixed with a small proportion of cornstarch, prevents clumping and ensures a smooth texture suitable for icing and dusting finished baked goods. The main component of this sugar is sucrose, which is a disaccharide composed of glucose and fructose.
The starch often used in this sugar mixture is derived from corn, known as cornstarch. It is useful due to its fine, powdery consistency and its ability to absorb moisture, which assists in keeping the confectioner's sugar dry. Cornstarch is a carbohydrate extracted from the endosperm of corn and is also used to thicken sauces and gravies.
It is interesting to note that sucrose is also the compound responsible for the formation of starch in plants like corn. When sucrose is broken down in the plant, it is used to make starch in the form of long chains of glucose molecules. This starch is then used in various culinary applications, including the making of confectioner's sugar.