Amylose

Amylose molecules have molecular weights ranging from 10⁴-20⁶. Amylose can form an extended shape (hydrodynamic radius 7-22 nm) but generally tends to wind up into a rather stiff left-handed single helix or form even stiffer parallel left-handed double helical junction zones. The interior of the helix contains only hydrogen atoms and is lipophilic, while the hydroxyl groups are positioned on the exterior of the coil as can be seen in figure 1a.  Most starches  contain about 25% amylose.  The two high amylose corn starches that are commercially available have apparent amylose contents of about 52% and 70-75%.