Amylose Crystallization From Concentrated Aqueous Solution: Role of Degree of Polymerization

In earlier research, we demonstrated that amylose forms a spherulitic morphology when crystallized from concentrated amylose - water solutions, over a wide degree of crystallization conditions. The process has been described as depending on a competition between crystallization and liquid-liquid phase separation processes. In the present study acid degradation and enzymatic debranching are utilized to create a number of amylose fractions differing in degree of polymerization, ranging from DPs of 20 to 920. It was determined (using DSC and x-ray diffraction) that the shorter the chain length, the higher the final degree of crystallinity. Atomic force microscopy is used to investigate the microstructure of amylose lamella within the spherulites.