Cereal Chem 38:187 - 193.  |  VIEW ARTICLE

Zone Electrophoresis Pattern of Free Amino Acids as an Index of Storage Condition of Wheat.

P. Linko. Copyright 1961 by the American Association of Cereal Chemists, Inc. 

Paper electrophoresis of free amino acids provided a rapid, simple, and convenient method to detect changes in the free amino acids of wheat during storage. Using 0.025M potassium-hydrogen-phthalate solution (pH 4.0) as buffer, a good resolution of aspartic, glutamic, gamma-aminobutyric, and neutral amino acids (as a group), as well as arginine and lysine, was obtained with 400 volts (14.0 V/cm.) during 90 minutes. For practical purposes 500 volts (18.5 V/cm.) and 30 minutes gave a satisfactory separation, yet no cooling was necessary. The electrophoresis patterns of free amino acids of wheats of good quality and high viability were characterized by a high glutamic acid peak, an average ratio of glutamic acid/aspartic acid peak height over 2, and a negligible gamma-aminobutyric acid peak. Glutamic acid peak and glutamic acid/aspartic acid peak height ratio decreased as deterioration increased. A marked gamma-aminobutyric acid peak was present without exception in electrophoresis patterns of wheats stored at unfavorable conditions. Dead wheats of extensive deterioration exhibited an increase in most of the free amino acids, including glutamic acid, largely due to protein breakdown. Glutamic acid peak increased markedly in germinated wheats, with moderate increases in aspartic and basic amino acids and little increase in gamma- aminobutyric acid.