Abstract
Summary The stale flavor of dried whole milk has been shown to exist in two forms which can be separated by CCl 4 -vapor distillation and Girard's-T extraction. One is nonvolatile under the conditions employed but can be extracted from the milk fat with Girard's-T reagent; the other is volatile and is not recovered from the Girard's-T extract after hydrolysis of the resulting hydrazones. The Girard's-T extractible component is recovered more completely from the fat when lower concentrations of Girard's-T reagent are used, a behavior similar to aldehydes. It can be separated by paper or column chromatography into a stationary and a mobile component which contains the flavor. The R f value of the mobile component is similar to that of the reaction product of heptaldehyde. It is readily decomposed by alkali or 2,4-dinitrophenylhydrazine in 4 m HCl. On treatment with 2,4-dinitrophenylhydrazine, at least four carbonyl compounds were obtained as decomposition products and tentatively identified by paper chromatography as acetaldehyde, propionaldehyde, acetone, and either 2-butanone or 2-pentanone. The CCl 4 -vapor distillates were found to contain at least seven carbonyl compounds, five of which have been identified as formaldehyde, acetaldehyde, propionaldehyde, acetone, and 2-penatone. The remaining two compounds possess the spectra and chromatographic characteristics of a saturated monocarbonyl compound and either an unsaturated dicarbonyl or hydroxycarbonyl compound. The stale-flavor component of this fraction appears to behave like a dicarbonyl compound with Girard's-T reagent.
Published Version
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