Twenty-two free amino acids from acetic acid extracts of wheat flour, unfermented and fermented (2.5 h) straight bread doughs, and bread samples are separated and quantitated by reversed-phase high-performance liquid chromatography of their dansyl derivatives. The chromatographic procedure is optimized by studying the influence of the absolute and relative amounts of dansyl chloride on the derivatization yield of amino acids. The effects of the ionic strength of the aqueous buffer and the choice of solvent on the separation of an amino acid standard mixture are also studied. Total amino acid content (particularly for ornithine and threonine) increases by 64% during mixing and undergoes a depletion of 55% during baking, glutamine, leucine, ornithine, arginine, lysine, and histidine being the most reactive amino acids.

This work was financed in part by the Comisión Interministerial de Ciencia y Tecnología (CICYT), Spain.