In most of the experiments on photosynthesis, we use a de-starched leaf or plant. What is the purpose of de-starching?

Destarching is the removal of starch from the leaf cells which is moved to the storage organs. The outcome of this will be an effective experiment on photosynthesis in which any presence starch will indicate photosynthesis after destarching.

Explanation: When all leaves are destarched, the leaves will not show any presence of starch. Therefore, when the experiments on photosynthesis are carried out, any starch present will be due to the photosynthesis that would have taken place after destarching.