What happens to the starch granule of the potato cell when lugol’s iodine solution was added

It turns dark blue when starch is present, and remains brown when starch is not present. This is basically because iodine forms a polypeptide complex with starch, resulting in the dark blue solution.  The amylose, or straight chain portion of starch, forms helices where iodine molecules assemble, forming a dark blue/black color.  The amylopectin, or branched portion of starch, forms much shorter helices and iodine molecules are unable to assemble, leading the color to be of an orange/yellow hue. As starch is broken down or hydrolyzed into smaller carbohydrate units, the blue-black color is not produced. (http://food.answers.com/Q/What_happens_to_the_potato_cell_as_iodine_solution_is_added)

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