The Molecular Constitution of Starch and the Mechanism of its Formation

Abstract

Two general conceptions have been prevalent regarding the chemical constitution of polysac-charides, namely 1), that this molecule is made up of a long chain of monosaccharide residues continuously linked by primary bonds and 2), that the molecules are simple elementary units consisting of relatively few anhydrosac-charides, held by primary valences, of crystalloidal dimensions. The elementary units were believed to possess the ability to form large molecules of colloidal dimensions. This second view is definitely being abandoned. The evidence and work in harmony with the first view are reviewed, such as the Haworth-Hirst concept; chain length of natural starches as determined by the end group assay method; Staudinger and Hausmann''s view that starch is a very large macromolecule; Freudenberg''s concept that dextrin consists of 5 anhydroglucose units joined by [alpha]-glucosidic linkages forming a ring.