Starch is the more frequent storage polysaccharide in plants. It is formed by a mixture of amylose (a linear polymer) and amylopectin (a branched polymer). Both kinds of polymer are made up of just glucose.

Starch in noodles has a substantial content of amylose, while starch in waxy rice has nearly only amylopectin. Amylose renders the dark blue colour typical of the Lugol reaction while amylopectin, with shorter helices, forms a brownish yellow complex with the iodine + iodide Lugol reagent.