Cereal Chem 61:222 - 228.  |  VIEW ARTICLE
Structure of Amylopectins Isolated from Large and Small Starch Granules of Normal and Waxy Barley.

A. W. MacGregor and J. E. Morgan. Copyright 1984 by the American Association of Cereal Chemists, Inc. 

Debranching, followed by gel-permeation chromatography on Biogel P-6, showed that amylopectins from large and small starch granules of normal and waxy barley contained three groups of unit chains having approximate degrees of polymerization (DPS) of 45-50, 18-20, and 10-12. Gel-permeation chromatography on Biogel P-4 separated the 18-20 and 10-12 DP groups into individual unit chains, showing that both groups were heterogeneous. Maltohexaose was the smallest unit chain found in the amylopectins studied. During beta-amylolysis, the 45-50 DP peak was degraded, and the predominant chain length was reduced to approximately 38 glucose units. The other two peaks were extensively degraded to give one heterogeneous peak having a predominant DP of 10-12. A new peak, composed of maltose and maltotriose stubs, was detected in the beta-limit dextrins. Amylopectins from the different types of starch granules studied appeared to have identical structures.