Starch and glycogen are composed of α-D-glucose units, where the -OH on the anomeric carbon (C1) is below the plane of the ring. Cellulose consists of β-D-glucose, where the anomeric -OH is above the plane of the ring. This simple difference makes starch digestible and cellulose indigestible to humans.
Starch and glycogen are composed of α-D-glucose units, where the -OH on the anomeric carbon (C1) is below the plane of the ring. Cellulose consists of β-D-glucose, where the anomeric -OH is above the plane of the ring. This simple difference makes starch digestible and cellulose indigestible to humans.