Understanding the Iodine Test for Starch
When food items containing starch are treated with iodine solution, a specific color change occurs. This is a fundamental test used in biology and chemistry to detect the presence of starch.

Color Change Result
- The color of the food items changes to **blue/black** when they contain starch.

Why Does This Happen?
- **Chemical Reaction**: Iodine (I₂) interacts with the starch molecules, specifically amylose, which is a component of starch.
- **Formation of Iodine-Starch Complex**: When iodine binds to amylose, it forms a complex that reveals a blue or black color. This is due to the helical structure of the amylose, which traps the iodine molecules.

Examples of Starch-Containing Foods
- Common foods that contain starch include:
- **Potatoes**
- **Rice**
- **Bread**
- **Pasta**

Importance of the Iodine Test
- The iodine test is widely used in laboratories to confirm the presence of starch in various substances.
- It helps in understanding the nutritional content of foods and is a practical application of chemistry in everyday life.
In summary, treating food items with iodine solution leads to a **blue/black** color change, indicating the presence of starch through a well-defined chemical interaction. This process is a vital tool in both educational settings and practical applications in nutrition and food science.