Beans pass through the * small intestine and arrive
in the large intestine undigested which
causes flatulence (
gas) to occur, also, beans contain more indigestible carbohydrates than most foods.
Raffinose is a sugar found in mushrooms, beans and in smaller amounts in some vegetables and grains. The human body lacks the enzyme called alpha-galactosidase to digest this sugar, so it ends up in the large intestine undigested which causes flatulence (gas) to occur.