Cereal Chem 40:121 - 128.  |  VIEW ARTICLE

The Protein Composition of Different Flours and Its Relationship to Nitrogen Content and Baking Performance.

P. M. Bell and D. H. Simmonds. Copyright 1963 by the American Association of Cereal Chemists, Inc. 

The proteins in a total of 26 flour samples ranging in nitrogen content from 1.49 to 2.92% dry weight were fractionated by differential extraction with 0.01M.sodium pyrophosphate (pH 7.0) and 0.05M formic acid (pH [approximately]3.5). The distribution of nitrogen in these extracts was correlated with total nitrogen and with baking performance. Except for four flours in this group there was a general tendency for baking quality to rise with increasing total nitrogen content. The exceptions included a durum wheat. In all cases, including the anomalous flours, there was a marked negative correlation between the total nitrogen and the percentage of that total extracted into sodium pyrophosphate. When the results were expressed as g. of nitrogen extracted into each solvent from 100 g. of flour, a very highly significant correlation was observed between total nitrogen and both pyrophosphate(r=0.592) and formic acid- (r=0.978) soluble nitrogen. Except for the four anomalous flours a positive but less highly significant correlation (r=0.632) was also observed between the formic acid-soluble nitrogen (g./100 g. flour) and baking score.