Abstract
The volatile carbonyl compounds in unheated miso-soup (aqueous miso homogenate) and heated miso-soup were swept off by nitrogen stream under reduced pressure at 3033°C, and were converted into 2, 4-dinitrophenylhydrazone derivatives.
Identification of these derivatives was carried out by means of thin layer chromatography, gas chromatography, ultraviolet spectrophotometry (300600 mμ) and infrared spectrometry.
Spectrometric and chromatographic assays indicated the existence of acetaldehyde, propionaldehyde, isobutyraldehyde, isovaleraldehyde, α-methylbutyraldehyde, furfural, diacetyl and some diketones in both unheated and heated miso-soup. In addition, n-capronaldehyde and formaldehyde were tentatively identified by gas chromatography.
A large amount of volatile carbonyl compounds developed when the unheated miso-soup was heated for 30 min at 100°C. Among the carbonyl compounds, remarkably increased acetaldehyde, isobutyraldehyde, isovaleraldehyde and α-methylbutyraldehyde.
