Cereal Chem 40:51 - 60.  |  VIEW ARTICLE

The Specific Surface of Flour and Starch Granules in a Hard Winter Wheat Flour and in Its Five Subsieve-Size Fractions.

R. Gracza and S. I. Greenberg. Copyright 1963 by the American Association of Cereal Chemists, Inc. 

The specific surface of starch granules in a Minnesota hard winter wheat patent flour, as obtained from the particle size distribution data using the Whitby centrifuge after proteolysis by Bromelin, was measured to be 0.7708 m[2]/g. If a correction is applied for the swelling in aqueous medium on the basis that the density decreases by the voluminal addition of water, the specific surface figure reduces to 0.7272 m[2]/g. This latter figure is about 3 to 4 times larger than that reported formerly on samples prepared either by dough washing in water drying and resuspension in water, or by digestion in pepsin and dilute hydrochloric acid with drying and resuspension in pentane before microscopic measurement. The specific surface of the parent flour was determined similarly to that of the starch granules. The value obtained was 0.1249 m[2]g. (i.e. about 4.5 times smaller than the total starch granule surface in the same flour). The ratio of total starch granule surface to the total flour surface in the five subsieve-size fractions of the parent flour increased from 1.34 in the finest fraction to 5.45 in the coarsest fraction, indicating larger starch granule surface exposed to atmospheric conditions, with flour of smaller particle size.