Starch, also known as farina, is contained in many products of plant origin. Its assimilation includes several stages. The first one concerns the digestion which happens thanks to the saliva, or amylase, to be more exact. It breaks down the starch to maltose (disaccharide). The next phase concerns the digestion in the stomach, in which process the pancreatic amylase engages too.
When consuming starchy foods, they have to be well chewed. For this purpose, there has to be produced enough saliva (salivary amylase) so as to boost the digestion. Otherwise, the digestion in the stomach will be slowed down since there are no amylolytic enzymes (amylase and maltase) to be produced in there.
The assimilation of starch takes up to half an hour. The last phase takes place in the small intestine, where the starch is fully assimilated. If the amount of such is too big, the pancreas gets exhausted since there has to be produced a larger quantity of ferments and maltose, which have to be converted into glucose. Keep in mind that when maltose is not converted into glucose, it starts decaying and is respectively turned into a poisonous substance, which, however, happens rarely.
Don't forget that the most essential part of the digestive process of starchy foods is their proper chewing!