Cereal Chem 52:387 - 395.  |  VIEW ARTICLE
Scanning Electron Microscopy of Soybeans, Soy Flours, Protein Concentrates, and Protein Isolates.

W. J. Wolf and F. L. Baker. Copyright 1975 by the American Association of Cereal Chemists, Inc. 

Soybean cotyledon fracture surfaces prepared by freezing in liquid nitrogen and samples of commercial soy flours, protein concentrates, and protein isolates were examined in the scanning electron microscope. Protein bodies and spherosomes characteristic of the native cellular structure were clearly discerned in the fracture surfaces and were also observed in a full-fat flour. Defatted flours likewise contained protein bodies; the largest number occurred in an unheated flour and the fewest were seen in a toasted flour. Protein concentrate made by alcohol leaching contained protein bodies, whereas a concentrate prepared by acid leaching consisted of partially collapsed spheres. The latter probably formed during spray drying of the neutralized concentrate. Isoelectric isolate particles were rough in surface texture and proteinate forms of isolates were smooth, apparently as a result of differences in solubility during spray drying.