What is the most stable 3D strucuture for starch?
The most stable three-dimensional structure for the (α1→ 4)-linked chains of starch and glycogen is a tightly coiled helix (Fig. 7-19), stabilized by interchain hydrogen bonds. For amylose, the core of the helix is of precisely the right dimensions to accommodate iodine as complex ions ( and ), giving an intensely blue complex. This interaction is a common qualitative test for amylose.