Final answer:
White sugar turns brown when caramelized due to the process of caramelization, which involves the breakdown and chemical reactions of sugar molecules. Heating sugar causes it to decompose into glucose and fructose, which then react further to form brown-colored caramel compounds.
Step-by-step explanation:
When white sugar is caramelized, it turns brown due to the process of caramelization. Caramelization occurs when sugar molecules are heated, causing them to break down and undergo various chemical reactions. In this process, heat causes the sugar molecules to lose water molecules and form new compounds, resulting in the formation of brown-colored compounds called caramel.
For example, when sucrose, which is the scientific name for table sugar, is heated, it decomposes into glucose and fructose. These simple sugars then react further to produce caramel compounds, which have a brown color. The browning and flavor development that occurs during caramelization are desirable in cooking and baking, as it adds a rich flavor and color to dishes such as caramel sauces, custards, and caramelized onions.