Plasticization and self assembly in the starch granule

Within a starch granule there are a range of length scales present ranging from the atomic, to supramolecular structures of > 100 nm that give rise to the growth rings arising as the starch is laid down. As the granule is formed, it is in a naturally hydrated state. This provides a degree of mobility permitting organization and self-assembly of the sidechain branches of the amylopectin. External factors that affect the ability of the branches to pack well are discussed here. Plasticization of the residues nearest to the amylopectin backbone is crucial. If the degree of plasticitation is insufficient (due to insufficient temperature or solvent) the double helical regions are disordered. Plasticization, this time of the amorphous growth rings, is also a necessary prerequisite for gelatinization.