Cereal Chem 48:168 - 181. | VIEW
Studies on the Extraction and Composition of Rice Endosperm Glutelin and Prolamin.
E. M. S. Tecson, B. V. Esmama, L. P. Lontok, and B. O. Juliano. Copyright 1971 by the American Association of Cereal Chemists, Inc.
Various extraction procedures were compared for the preparation of glutelin from milled rice (variety IR8). Extraction of protein with 0.015N sodium hydroxide before fractionation resulted in glutelin with 6% lysine. Glutelin preparations extracted after removal of albumin-globulin and prolamin had aminograms similar to those of whole milled-rice protein. Subfractionation of rice glutelin in the presence of beta- mercaptoethanol or detergent gave products differing widely in amino acid composition and electrophoretic mobility. Although glutelin had a molecular weight of 6 x 10(5), as measured by gel filtration, reduced glutelin showed a second fraction with a molecular weight of 6 x 10(4). Prolamin prepared by ethanol extraction had a low protein content and a high UV absorption which are indicative of polyphenols. The UV-absorbing contaminant dissociates from the prolamin in an alkaline solution and is more soluble in ethanol than prolamin. Acetone precipitation from the ethanol extract resulted in a pure prolamin preparation.