Cereal Chem 56:220 - 226.  |  VIEW ARTICLE
Defatted and Reconstituted Wheat Flours. IV. Effects of Flour Lipids on Protein Extractability from Flours that Vary in Bread-Making Quality.

O. K. Chung, Y. Pomeranz, E. C. Hwang, and E. Dikeman. Copyright 1979 by the American Association of Cereal Chemists, Inc. 

A poor quality flour and two good quality flours were defatted with Skelly B, benzene, acetone, and 2- propanol, listed in the order of increasing ability to remove polar lipids. Protein extractability with 0.01M sodium phrophosphate (Na-pp) buffer, 0.005N acetic acid (AcOH), or 3M urea in Na-pp buffer decreased curvilinearly with increasing lipid removal. Decreases were greater for gluten (urea or AcOH extracts) than for albumin and globulin (Na-pp extracts) proteins. The decreased protein solubilities of defatted flours were, to a large extent, restored when the defatted flours were reconstituted with their respective extracted nonpolar or total (nonpolar plus polar) lipids, but not with polar lipids alone. Protein solubility, like bread- making quality, was almost completely restored when lipids extracted with Skelly B were returned to the defatted flour, but not when 2-propanol extracted lipids were recombined with their flour residue. The effects of lipids on protein extractability in flour depended on the quantities and types of lipids and their association with proteins. Urea extraction differentiated best between good and poor quality flours; 0.05N AcOH extraction appeared to be a more sensitive indicator of the relation between protein extractability and bread-making characteristics (especially mixing time) of flour reconstituted with lipids.