L. Wiseblatt and F. E. Kohn. Copyright 1960 by the American Association of Cereal Chemists, Inc.
Volatile compounds in freshly baked bread are recovered with minimal decomposition by vacuum pumping from a steam-jacketed vessel containing the coarsely shredded bread. Efficient traps are necessary to condense the more volatile materials. The total condensate is treated to remove organic acids, and then the carbonyl compounds are converted to 2,4-dinitrophenyl-hydrazones (DNPH's). Separate aliquots are used to investigate alcohols and esters. No qualitative evidence has been found for the presence of phenolic compounds or amines. The DNPH's have been separated by repeated adsorption chromatography on activated silica gel columns and, to a lesser degree, by paper chromatography. The aldehydes identified in this way are acetaldehyde, crotonaldehyde, 2-ethylhexanal, and furfural; the ketones are acetone, hexanone-2, heptanone-3; dicarbonyl compounds are diacetyl and methylglyoxal; pyruvic and levulinic acids are also present, possibly in the form of their ethyl esters. Several other DNPH's have not been identified positively. Quantitative estimations have been made of some of the volatile compounds, and the data used in attempts to impart a typical breadlike flavor to a very bland, chemically leavened product. These attempts were unsuccessful, whether the treatment was applied to the dough ingredients or (by aeration) to slices of the freshly baked product.