Commercial Delicious apple essence was extracted to yield an oil with a strong apple-like aroma.This oil was separated into its components with high-resolution packed and opentubular gas chromatographic columns. Fiftysix compounds were identified, mainly by a combination of mass spectrometry and gas-chromatographic retention data. While many of these compounds contribute to over-all Delicious apple essence aroma, the main components directly associated with characteristic apple-like aroma were ethyl 2-methylbutyrate, hexanal, and 2-hexenal.
The synthesis, mass spectra, and infrared spectra are described for four new 2-methoxy-3-alkylpyrazines with alkyl groups hexyl, propyl, isopropyl, and ethyl. The odor thresholds of the hexyl, propyl, isopropyl, and ethyl compounds were found to be 1, 6, 2, and 425 parts of compound per 1012 parts of water, respectively. The odor character of these four compounds compared to that of the known bell pepper component 2-methoxy-3-iso-butylpyrazine are described as very similar for the hexyl and propyl, moderately similar for the isopropyl, and not similar for the ethyl. The related
2 µ; nmr (CCI4) 0.84 and 0.86 (two s, 6 H, CH3CCH3), 1.08, (a shoulder due to CH3CH) of a singlet at 1.1 (total 6 H, CH3CC=0), 1.93 (m, 3 H, CH2CCH); mass spectrum m/e 220 (molecular ion), 41, 97, 109, 110, 39. Peak (dihydro-d-patchoulenone 9) had the following characteristics: ir, nmr, and mass spectral data were superimposable with those of the saturated ketone 9 obtained by the oxidation of alcohol 8.
Nine additional components of the oxygenated fraction of the steam volatile oil of carrot roots were identified using direct-capillary gas-liquid chromatography-mass spectrometry and packed-column gas-liquid chromatography-batch infrared spectrometry. These components were geranyl 2-methylbutyrate, geranyl isobutyrate, d-ionone, geranylacetone, p-cymen-8-ol, elemicin, eugenol, p-vinylguaiacol, and 4-methylisopropenylbenzene. A compound with a raw carrotlike aroma was isolated but could not be positively identified.The systematic control of the flavor of carrots in both their production and processing requires a knowledge of the volatile constituents of carrots important to their aroma and flavor. A knowledge of the nature of the volatile
The feasibility and advantages of using a capillary chromatographic column directly with a time‐of‐flight mass spectrometer were demonstrated in the analysis of several flavor extracts. The high resolving power of this column proved to be indispensable in cases where chromatographic fractions previously unresolved showed similar mass spectra. Other limitations of this combined technique are covered.
for amorphous bulk polymers by Mandelkern, Quinn, and Flory (70). In their interesting paper, these authors explained the observed induction period and crystallization kinetics in terms of the concept of concurrent nucleation and crystal growth, just as has been done in the present work.The present measurements were all made at one temperature. It would be of considerable interest to obtain data at several temperatures in order to determine the temperature coefficients of k and t and to evaluate the effect of temperature on the crystallization kinetics.
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