Cereal Chem 38:507 - 515.  |  VIEW ARTICLE

Identification of Carbonyl Compounds Produced in Pre-ferments.

B. S. Miller, J. A. Johnson, and R. J. Robinson. Copyright 1961 by the American Association of Cereal Chemists, Inc. 

Extraction of a pre-ferment with diethyl ether or of the condensed gases with carbon tetrachloride was ineffective for obtaining sufficient minor flavor constituents for analysis by gas chromatography using thermistors as detectors. Passing the natural gases from a pre-ferment through 2,4-dinitrophenylhydrazine reagent was a convenient way of isolating carbonyl compounds in reasonable quantity. Nitrogen also was effective for sweeping the carbonyl compounds from a pre-ferment. Formaldehyde, acetaldehyde, acetone, isobutyraldehyde, n-butyraldehyde methylethylketone, isovaleraldehyde, and n-valeraldehyde were detected by gas chromatography of the precipitated carbonyl derivatives by heating the mixed hydrazones in the presence of alpha-ketoglutaric acid. All of these but n-valeraldehyde were isolated from the precipitated mixture by passing in through a Celite column. In addition, 2-methyl-1-butanal was isolated by column chromatography. Individual components were identified by comparing them with authentic compounds using paper chromatography in two different solvents and by ultraviolet and infrared spectral analyses.