Cereal Chem 59:276 - 278.  |  VIEW ARTICLE
Effect of Nitrogen Fertilization on Quantity and Composition of Wheat Flour Protein.

G. J. Doekes and L. M. J. Wennekes. Copyright 1982 by the American Association of Cereal Chemists, Inc. 

A fractionation method was developed to determine whether the composition of wheat flour protein is related to total protein content. Starch gel electrophoresis showed that two extractions with 70% ethanol and one extraction with 40% ethanol + 0.1M Na2SO4, extracted all of the gliadins, albumins, and globulins from flour. Dialysis of the combined extracts against 0.4M Na2SO4 precipitated the gliadins specifically. The protein in the residue was glutenin. Application of the method to a series of flour samples with increasing protein contents, obtained from nitrogen-fertilized wheat cultivars, showed that only the gliadin content (expressed in milligrams per gram of flour) increased. All the flour samples, regardless of cultivar or total protein content, had the same average amounts of albumin and globulin, ie, 1.6 mg of N per gram of flour. The glutenin contents of the flour samples were also independent of the total protein contents, but differed among cultivars. Glutenin content proved to be related to both baking quality and grain hardness. In each cultivar, the gliadin-to-glutenin ratio increased with loaf volume.