Water-soluble amylose: Preparation and properties

A dry form of amylose has been prepared that is easily soluble in water at all temperatures. It can go into solution even at high concentrations (up to 10%), forming very viscous liquids that are indistinguishable in appearance and properties from those prepared by autoclaving of retrograded amyloses. The solutions gel spontaneously upon standing. Two criteria were found to be important in the preparation of water soluble amyloses: first, their molecular weight has to exceed 200,000; secondly, they must be dried from solution in a rapid manner, such as by drum- or spray-drying. Data from x-ray diffraction, infrared absorption, and iodine and water vapor absorption indicate the material to be an amorphous, substantially unbonded form of amylose, free of significant amounts of helical configuration. Data from β-amylase digestion limits and intrinsic viscosities on the water solutions of these amyloses indicate that they form true solutions in water and not merely dispersions.