Single crystals of amylose with a low degree of polymerization

Single crystals of amylose with a low degree of polymerization were prepared from dilute solution in water or mixtures of water and ethanol. Depending on the concentration of ethanol used, three different polymorphs resulted. From pure water amylose B was obtained and, respectively, from 15% (v/v) ethanol, amylose A, and from 40% (v/v) ethanol, V amylose. The crystals were studied by electron diffraction after quench-freezing and the crystallographic parameters were compared with those already reported in the literature.