What causes particles of food in stool with chronic constipation?

Inadequate chewing?: Many foodstuffs, especially vegetable matter may appear to be relatively undigested and recognizable in stool -- corn is a common sighting. Adequate mastication (chewing) helps start the digestive process, breaking food into smaller more digestible pieces, allowing enzymes to break down and begin absorption of nutrients. The husk is hard to digest, and thus often visible.