How will you test the starch in a food item?

The presence of starch in a food item can be tested using an iodine solution test.

To perform the test, take a small quantity of the food item and place it on a plate or in a test tube. Then add 2–3 drops of dilute iodine solution to it. If the food item turns blue-black in colour, it indicates the presence of starch.

This happens because iodine reacts with starch to produce a blue-black colour. Foods such as potatoes, rice, bread, and wheat usually give a positive test for starch.