An Investigation of Varietal Differences in the Iodine‐Binding Capacities of Crystalline Rice Amylosesa

摘要

SUMMARYPurified amyloses have been obtained from four widely different varieties of rice by alcohol fractionation of the corresponding starch. Each variety of amylose was found to bind 18.9 mg of iodine per 100 mg of amylose on the basis of solvent‐free carbohydrate. Viscosity measurements in potassium hydroxide solutions have made possible the calculation of the viscosity‐average molecular weights. These molecular weights were found to be: Century Patna 231, 100,000; Caloro, 140,000; Rexoro, 325,000; and Zenith, 310,000. Beta‐amylase action on Century Patna and Rexoro amyloses indicated that the structures of both were si