Cereal Chem 55:127 - 137. | VIEW
An Investigation of the Alpha-Amylase from Self-Liquefying Barley Starch.
B. W. DeHaas, D. W. Chapman, and K. J. Goering. Copyright 1978 by the American Association of Cereal Chemists, Inc.
Starch prepared from Washonupana, a short awn hulless waxy barley developed at Montana State University, has an associated enzyme that will liquefy the starch. With Washonupana starch the Brabender curves attain a maximum value and then the viscosity drops rapidly, but HgCl2 negates the effect of the enzyme and results in a normal Brabender viscosity curve for a waxy barley starch. Addition of HgCl2 results in increased viscosity obtained on cooling for several other barley starches; apparently these starches also have traces of associated enzyme. The enzyme associated with Washonupana starch behaves like an alpha-amylase. The enzyme releases dye from a Cibachron Blue-Amylose complex, is enhanced at lower pH levels by the addition of calcium ions, and has an optimum pH level of 5.3. The enzyme is fairly thermo-stable, maintaining activity at temperatures of 50-60 C. The products of the autolysis were studied by high pressure liquid chromatography. The principal sugars following digestion at 50 C were glucose, maltose, and maltotriose, but digestion at 60 C yielded higher oligosaccharides, with maltose and G6 being the predominant fractions.