Studies on Rye Starch Properties and Modification. Part I: Composition and Properties of Rye Starch Granules

Publisher Website
Google Scholar
Abstract
Rye is considered as a potential raw material for starch industry. Starting from a survey of technical procedures of isolating starches from rye‐flour and ‐grits investigations will be reported, which were performed on pilot plant‐ and laboratory‐isolated rye starches. The present paper deals with its granule appearance and composition.A distribution of granule size between small granules (⩽ 10 μ − 15%) and large granules (⩾ 11 … ⩽ 40 μ − 85%) is typical for the totality of the starches. Differing distributions depend on the conditions of isolation: the entity of starch containing samples resulted from the laboratory procedures under investigation. Large‐granule starch preparations were isolated in the pilot plant: the centrifuge‐overflow contains the small‐granule fraction which is high in impurities. Granule crystallinity amounts to 16%. The crystalline component ‐ like in wheat and triticale starches ‐ consists predominatly of A‐polymorph ‐ with up to 9% of the B‐type. The isotherms of water exchange are of the cereal type.The contents of minor constituents largely relate to the small granule fraction which assembles the majority of crude protein, pentosans and lipids, which are difficult to remove Large granule samples may be produced in high purity (⩽ 0,2% crude protein) . Lipid components in all fractions influence the results of linear chain‐iodine interactions and they must be removed to proceed from apparent to absolute polysac‐charide indices. The absolute amylose contents amount to ∼ 25% for large granule samples and to 20–21% for small granule samples. The average chain‐length of iodine binding helical regions was determined with 220–240 AGU.