alpha-galactosides of sucrose in foods: Composition, flatulence-causing effects, and removal

Alpha-galactosides of sucrose, namely raffinose, stachyose and verbascose, are widely distributed in higher plants, especially leguminous seeds. In addition the presence of galactopinitol, galactinol, mannitriose and melibiose in Brassica campestris, soybean and some legumes has been reported. Due to the absence of alpha-galactosidase activity in human and animal intestine mucosa, these oligosaccharides escape digestion and they are metabolized by bacteria to hydrogen, carbon dioxide and methane. Thus, they are considered to be the principal flatulence-causing factors present in food of plant origin. Furthermore, starch and hemicellulose may contribute to flatulence. A significant positive correlation, between the hydrogen production by rat and the content of alpha-galactosides of sucrose in legumes consumed, has been reported. Various methods for the removal of flatulence causing oligosaccharides including dehulling, soaking and/or cooking in water and in buffer solutions, irradiation, enzymatic treatment, germination and solvent extraction have been investigated. The pros and cons of these procedures are discussed.