Cereal Chem 61:53 - 59.  |  VIEW ARTICLE
Wheat, Wheat-Rye, and Rye Dough and Bread Studied by Scanning Electron Microscopy.

Y. Pomeranz, D. Meyer, and W. Seibel. Copyright 1984 by the American Association of Cereal Chemists, Inc. 

Three types of bread (100% white wheat flour, 60% wheat-40% rye flours, and 90% rye meal-10% rye flour) were examined by scanning electron microscopy along with appropriate samples drawn during dough mixing, various stages of sourdough production and fermentation, and baking. In white wheat flour doughs, structure was based primarily on formation of a protein matrix. Large starch granules and especially "stringing" of small starch granules contribute to dough structure in white wheat flour systems. In the bread, interaction occurs between protein and swollen starch (mainly large granules). Much of the starc h is modified, but in some "protected" crumb and crust areas (inside vacuoles), little modifications, especially of small starch granules, was observed. In the mixed wheat-rye system, some contribution is from gumlike substances and from modifications of gluten and starch by organic acids. In rye meal systems, gum materials facilitate stringing of small starch granules and their adherence to large granules. Whereas in white wheat or mixed wheat-rye meal systems, pericarp-aleurone particles are part of the problem, in the rye meal system they are part of the solution of providing a coherent and continuous dough or bread structure. The major contributor to rye meal bread structure is modified starch. The rye meal bread crust, unlike the crust of wheat and mixed wheat-rye flour bread, is coarse and affected by the presence of particles rich in aleurone-pericarp.