STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES: LXI. PROPERTIES OF THE FRACTIONATED NITRATES OF TWO FRACTIONS OF CORN STARCH

Abstract

Corn starch has been separated into two individual components, arbitrarily designated as amylose (linear fraction) and amylopectin (branched-chain fraction) by means of preferential adsorption on cellulose (Tanret–Pacsu method). These components have been nitrated and their nitrates fractionated by dissolution in ethanol. The relative stabilities and nitrogen contents of the nitrated fractions have been studied.Unfractionated amylose nitrate has greater stability than unfractionated amylopectin nitrate as judged by the Bergmann–Junk test. Dissolution methods of fractionation showed a much higher solubility of the amylopectin nitrate, the greater relative stability of the amylose fractions, and the somewhat greater stabilizing action of ethanol in the case of the latter.The widely different solubilities of amylose and amylopectin nitrates in conjunction with the lower ethanol solubility of whole starch nitrate are in accordance with the theory of a branched-chain structure for amylopectin and the linear type for amylose.