BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Starch Test: Add Iodine-KI reagent to a solution or directly on a potato or other materials such as bread, crackers, or flour. A blue-black color results if starch is present. If starch amylose is not present, then the color will stay orange or yellow.

Detailed explanation-2: -Amylose present in starch is the reason for change in its colour to blue black. Iodine is not soluble in water so it is dissolved along with potassium iodide that forms a triiodide molecule which enters the helical structure of amylose and changes the colour of starch.

Detailed explanation-3: -Iodine-KI Reagent: Iodine does not completely soluble in liquids, so the iodine reagent is formulated in the presence of potassium iodide by breaking down iodine in liquids. This creates the complex of a linear triiodide ion soluble, which slides into the starch coil, creating a vivid blue-black appearance.

Detailed explanation-4: -Dilute iodine solution is used to test the presence of starch in solutions. 2-3 drops of iodine solution are added to the solution to be tested. A blue-black colour appears if starch is present.

Detailed explanation-5: -Iodine solution is used to test the presence of starch in food materials. When iodine solution is added to a food item, it turns into blue-black colour if starch is present.