Transitions of Crystallites in Granular Starch

Starch source Birefringence loss,% X-ray crystallinity loss,% Molecular order loss (13C-CP/ MAS NMR),% Molecular order loss (DSC),% 

Aqueous solutions of amylose are quite unstable, and on cooling to room temperature show turbidity development and eventually form a precipitate or a gel depending on concentration and molecular size of the polymer chain. Gidley and Bulpin393 have 

Besides the formation of an elastic network, amylose gelation is also characterized by the development of opacity, which is generally attributed to chain aggregation.197,400 401 For a polydisperse amylose preparation (DP 3080, 2.4% solution, quenched to 32°C), the increase in turbidity slightly preceded the onset of G development.197 Crystallization, as detected by x-ray diffraction (intensity of the 100 diffraction peak), 

In contrast to amylose, amylopectin gel stiffness does not show a strong dependence on concentration for waxy maize amylopectin gels (10-25% w/w), stored for six weeks at 1°C, the modulus varied linearly with concentration.196 Durrani and Donald409 reported a C16 relationship between modulus and concentration. The Clark 

Of importance to the microstructure and viscoelastic properties of starch gels is the identified thermodynamic incompatibility of starch polysaccharides.417 Amylose 

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