D-Raffinose is a trisaccharide composed of galactose, glucose and fructose. It can be found in beans, cabbage, brussels sprouts, broccoli, asparagus and whole grains. Raffinose is hydrolyzed to D-galactose and sucrose by α-galactosidase, which is not found in the human digestive tract. Raffinose passes through the stomach and small intestine intact. In the colon, it is fermented by gas-producing bacteria which do have the α-galactosidase enzyme. Depending on the bacterial species, they produce carbon dioxide, methane or hydrogen, leading to the flatulence commonly associated with eating beans and other vegetables.