Polysaccharides are found largely in foods that happen to be high in carbs such as bread, pasta pastries and cookies. Pasta is composed largely of digestible polysaccharides. Polysaccharide sources include plant foods like starch which is found in grains such as wheat, oats and rye, and potatoes and legumes like peas, beans and lentils.
They are also found in animal foods such as shellfish and animal liver and in the shells of crustaceans like crab and shrimp. Polysaccharides are a stored form of energy which also gives structures to plants. There are artificial and natural occurring polysaccharides that are added to commercial foods as thickeners or fibers.