Cereal Chem 42:140 - 148.  |  VIEW ARTICLE

The Amino Acid Composition of Hard Wheat Varieties As a Function of Nitrogen Content.

F. N. Hepburn and W. B. Bradley. Copyright 1965 by the American Association of Cereal Chemists, Inc. 

Samples of commercial wheats, representing different types and different amounts of total nitrogen content, were found to differ in the proportion of certain amino acids. Samples of pure varieties of spring and winter hard wheats were selected to permit comparisons of the amino acid composition between 1) different varieties at a single level of total nitrogen and 2) between samples of varieties which differed widely in nitrogen content. The proportions of amino acids were nearly constant for all varieties of wheat in samples of similar nitrogen content, although cystine and methionine tended to be higher in the spring wheats. Samples of the highest and lowest ranges of nitrogen exhibited different proportions of most amino acids, but the differences were small relative to the magnitude of the difference in total nitrogen. Histidine, isoleucine, and tyrosine showed the least variation with nitrogen level. Values for glutamic acid, phenylalanine, and proline tended to be higher in high-protein samples, whereas the remaining amino acids showed the reverse trend to varying degrees.