Comparison of X-ray diffraction patterns and sorption properties of the hydrolyzed starches of potato, wrinkled and smooth pea, broad bean and wheat

Abstract

The hydrolysis of native starches by hydrochloric acid (the so-called lintnerization process) yields a more crystalline material with moderately decreased water sorption capacities. X-ray diffraction may be used to rank native or lintnered starches from B to A type with intermediate type C mixtures and this change in order is parallelled by decreasing water affinities. The dependence of the intensity of the X-ray diffractogram on the water contents required for the A and B lattice spacings confirms the intimate rôle of water in the amylose crystalline structure. Both structural and hydration hysteresis remain important in crystalline rich materials, suggesting that the mechanisms involved are not limited to long range interactions or mechanical tensions.