Thomas R. Kemp

3,6-Nonadien-1-ol from Citrullus vulgaris and Cucumis melo

Abstract cis , cis -3,6-Nonadien-1-ol isolated from watermelon and previously from muskmelon by vacuum steam distillation-extraction, was identified by int

cis-6-Nonenal: A flavor component of muskmelon fruit

Abstract cis -6-Nonenal, a compound with melon-like flavor, has been isolated from muskmelon fruit by vacuum steam distillation. The concentration of cis -6-nonenal in fruit exceeds the flavor threshold concentration in aqueous solution.

Volatile Cucumis melo components: Identification of additional compounds and effects of storage conditions

Abstract Additional volatile compounds were isolated from muskmelon fruit by means of a water recycling apparatus, separated by GLC, and identified principally by MS and GLC retention data. Compounds reported for the first time as melon components are: n -hexanol, 1-octen-3-ol, cis -3-nonen-1-ol, n -butyl acetate, iso butyl acetate, 2-methylbutyl acetate, n -hexyl acetate, ethyl n -butyrate, ethyl 2-methylbutyrate, benzyl acetate, β-phenethyl acetate, and γ-phenylpropyl acetate. Muskmelon fruit stored frozen prior to steam distillation-extraction yielded an essence which, when compared with that obtained from freshly harvested fruit, contained considerably larger amounts of trans -2-nonenal, n -nonanol, cis -3-nonen-1-ol, cis -6-nonen-1-ol, and the methyl and ethyl esters of linoleic and linolenic acids. Marked decreases in the relative amounts of benzyl acetate, β-phenethyl acetate, and γ-phenylpropyl acetate resulted from freezing. All 21 compounds examined were present in the essences prepared from fresh, refrigerated, and frozen fruit.

Characterization of some volatile components of muskmelon fruit

Abstract Muskmelon fruit oil obtained by vacuum steam distillation at 60–70° was shown to contain n -octanol, n -nonanol, 2-nonenal, 2-nonenol, n -octyl acetate, n -octyl butyrate, β-ionone, methyl palmitate, methyl palmitoleate, methyl oleate, methyl linoleate, methyl linolenate, ethyl palmitate, ethyl palmitoleate, ethyl oleate, ethyl linoleate, ethyl linolenate. The identities of compounds were confirmed by direct comparison of their mass spectra and GLC retention data with those of authentic samples. Other compounds tentatively identified on the basis of mass spectral data were nonadienol, nonenol, octyl hexanoate and butyl palmitoleate. The nonadienol was associated with the muskmelon-like aroma.

Identification of some volatile compounds from Citrullus vulgaris

Abstract Volatile compounds from watermelon ( Citrullus vulgaris obtained by vacuum steam distillation—extraction of the fruit at 60–70° in a water-recycling apparatus, were separated by gas chromatography and subjected to spectral analyses. Evidence was obtained for the following new constituents, hexanal, trans -2-heptenal, trans -2-octenal, nonanal, trans -2-nonenal, trans , cis -2,6-nonadienal, nonan-1-ol, trans -2-nonen-1-ol, cis -3-nonen-1-ol, trans , cis -2,6-nonadien-1-ol, trans -2-decenal, trans -2-undecenal, geranial and β-ionone.

Characterization of some new C16 and C17 unsaturated fatty aldehydes

The following six volatile fatty aldehydes, including five new compounds have been characterized by spectral analyses (mass spectra presented) and ozonolysis:cis-7-hexadecenal,cis-8-heptadecenal (previously known),cis,cis-7,10-hexadecadienal,cis,cis-8,11-heptadecadienal,cis,cis,cis-7,10,13-hexadecatrienal,cis,cis,cis-8,11,14-heptadecatrienal. Compounds were separated (gas liquid chromatography) from a volatile concentrate prepared by reduced pressure steam distillation of an aqueous cucumber homogenate. These aldehydes were not detected by our methods when the tissue was extracted with CHCl3-MeOH.

Aromatic hydrocarbons: Examination of peach fruit and foliage volatiles

Abstract Peach fruit volatiles obtained by steam distillation contained 1,2-dihydro-1,1,6-trimethylnaphthalene while foliage volatiles also contained this compound in addition to 1,2,3,4-tetrahydro-1,1,6-trimethylnaphthalene (ionene) and two C 14 H 22 hydrocarbons. Other compounds isolated from foliage were hexanal, trans -2-hexenal, trans -3-hexen-1-ol, benzaldehyde, nonanal, methyl salicylate and eugenol.

1,2-Dihydro-1,1,6-trimethylnaphthalene from strawberry oil

Abstract 1,2-Dihydro-1,1,6-trimethylnaphthalene (3,4-dehydroionene) has been identified in the essential oil of strawberry fruit and foliage.

High-resolution gas chromatography of methylated ribonucleosides and hypermodified adenosines : Evaluation of trimethylsilyl derivatization and split and splitless operation modes

Abstract Methylated ribonucleosides and hypermodified adenosines were trimethylsilylated on chromatographed by high-resolution gas chromatography on a fused-silica capillary column operated in split and splitless modes. Evaluation of micro-silylation (50-μl volume) of methylated ribonucleosides showed that N,O-bis(trimethylsilyl)trifluoracetamide (BSTFA) and pyridine at 150°C gave greater yields than silylation with either BSTFA alone or BSTFA and pyridine at 75%C. N-Methyl-N-trimethylsilyltrifluoracetamide gave lower yields of derivatives of N 6 -substituted adenosines, such as N 6 -methyladenosine, relative to those obtained with BSTFA. Methylated ribonucleosides generally gave sharp, symmetrical peaks on the SE-54 column operated in the split mode; however, the compound were not as well resolved as the cytokinin-active hypermodified adenosines on the relatively non-polar SE-54 stationary phase. The splitless operation mode employing a cold trapping procedure (40°C initial temperature) yielded sharp peaks and nanogram quantities of N 6 -methyladenosine were detectable. Most hypermodified adenosines separated well from other compounds, although several peaks of unknown composition eluted in the same chromatographic region as the methylated ribonucleosides when the cold trapping splitless technique was used.

A C15 aldehyde from Cucumis sativus

Abstract cis -8-Pentadecenal was isolated from a concentrate of cucumber volatiles and characterized by spectral analyses and ozonolysis. The biochemical origin of this compound and other long chain aldehydes isolated from cucumber is discussed.