Cereal Chem 67:258-260   |  VIEW ARTICLE

Study of Wheat Starch Granule Surface Proteins from Chlorinated Wheat Flours.

M. Seguchi. Copyright 1990 by the American Association of Cereal Chemists, Inc. 

After wheat starch granules were collected from chlorinated wheat flour (chlorination level: 0.0, 0.5, 1.0, 1.5, and 2.0 g of Cl2 gas per kilogram of wheat flour) by acetic acid fractionation, the starch granule surface proteins were successively extracted from them with a 1% sodium dodecyl sulfate (SDS) solution containing 1% 2-mercaptoethanol at room temperature. The treated prime starch granules could not be stained with amido black 10B, which shows that almost all of the starch granule surface proteins were excluded in this process. Ultraviolet spectra (200-420 nm) of this broad range of extracted surface proteins showed proportional increases of the absorbance of ultraviolet light with chlorination levels. The amounts of these starch granule surface proteins pergram of wheat starch granules estimated by the Lowry and ninhydrin methods, respectively, showed a similar increase with chlorination levels. These surface proteins were further subjected to SDS slab gel electrophoresis and Sephadex G-150 column chromatography, which showed that chlorination produced a slight polymerization of some larger molecular weight proteins in the surface. The chlorine content in these starch granule surface proteins was then measured by fluorescent X- ray analysis, which showed that the content of molecular bound chlorine also proportionally increased with chlorination levels.