To make clear the distinctive odorants of fish sauce, addition tests were carried out with respect to deodorized fish sauce samples. Volatiles from the headspace gas of nontreated fish sauce and deodorized fish sauce were characterized by gas chromatography-olfactometry and gas chromatography-mass spectrometry. Four compounds contributing to the distinctive odor of fish sauce were 2-methylpropanal, 2-methylbutanal, 2-ethylpyridine, and dimethyl trisulfide. Addition tests (quantitative descriptive analysis) with respect to the four odorants showed that contributors to the fishy aroma were 2-ethylpyridine and dimethyl trisulfide and that all four odorants contributed to the sweaty aroma. Furthermore, the fecal note of fish sauce was essential with 2-ethylpyridine and dimethyl trisulfide, and the rancid note was essential with all four odorants.
Aroma concentrate separated from an aqueous solution of Haze honey by
adsorptive column
chromatography had a stronger aroma intensity than that separated by a
combination of a
preliminary extraction with acetone and separation of volatile
compounds from acetone extract by
steam distillation extraction. A total of 130 compounds were
identified, including 27 alcohols, 19
aldehydes, 9 ketones, 12 esters, 8 acids, 35 hydrocarbons, 10 furanoids
or pyranoids, and 10
miscellaneous compounds. The sensory importance of the volatile
compounds was investigated by
sniffing the fractions separated by preparative gas chromatography.
As a result, benzeneacetaldehyde, linalool, phenethyl alcohol, p-cresol,
p-anisaldehyde, methyl-p-anisaldehydes,
trimethoxybenzene, 5-hydroxy-2-methyl-4H-pyran-4-one, and lilac
aldehydes seemed to contribute to Haze honey
aroma.
Keywords: Aroma compounds; flavor components; honey; column
concentration
Voltile flavor compounds in sesame seed oil were investigated. Commercially processed sesame seed oil was steam distilled under reduced pressure, and volatiles from the distillate were separated by an adsorptive column method. Among 171 individual peaks detected, 134 peaks were definitely or tentatively identified by analysis of mass spectra and modified Kovats indices. To elucidate the compounds directly contributing to the characteristic flavor, the odor concentrate was fractionated by silica gel thin-layer chromatography and preparative gas chromatography. As a result, 1-(5-methyl-2-furanyl)-1-propanone, 3-formylthiophene, 2-propyl-4-methylthiazole, 2-ethyl-4-methyl-1H-pyrrole, 2-ethyl-6-methylpyrazine, 2-ethyl-5-methylpyrazine, 4,5-dimethylisothiazole, 4,5-dimethylthiazole, 2,6-diethylpyrazine, 2-ethyl-2,5-dimethylpyrazine, 1-(2-pyridinyl)ethanone, and 1-(1-methyl-1H-pyrrol-2-yl)ethanone were considered to be principal contributors of sesame seed oil flavor.
Volatiles from the headspace gas of fish sauce with no change in the pH
(pH as is) were trapped in
a Tenax TA column and analyzed by gas chromatography (GC) and GC-mass
spectrometry (MS).
Fish sauce was alkalized (pH 11.0) to enhance the
release of nitrogenous and sulfurous compounds
and was likewise analyzed. About 124 volatile compounds, including
20 nitrogen-containing
compounds, 20 alcohols, 18 sulfur-containing compounds, 16 ketones, 10
aromatic hydrocarbons, 8
acids, 8 aldehydes, 8 esters, 4 furans, and 12 miscellaneous compounds,
were definitely and
tentatively identified. Detection of highly volatile nitrogenous
and sulfurous compounds such as
trimethylamine and dimethyl disulfide, which could not be easily
detected by already existing
methods, was enhanced after alkalization.
Keywords: Headspace gas; volatile compounds; odor; fish sauce
Lactobacillus brevis and Saccharomyces cerevisiae were completely sterilized by the supercritical (SC) CO2 micro-bubble method. Gaseous (G) and liquid (LQ) CO2 were used in a similar manner to compare the sterilizing effect. Among the three treatments, the microorganisms were only effectively sterilized by the SC CO2 treatment at 25 MPa and 35 degrees C.
The application of microbubbles of pressured CO 2 greatly increased CO 2 concentration in the solution treated. By treatment at 6 MPa, 35ЊC and average residence time 15 min, L. brevis was completely inactivated at the level of dissolved CO 2 , ␥ м11 (␥, Kuenen's gas absorption coefficient). E. coli and S. cerevisiae required ␥ м 17, and T. versatilis required ␥ м 21 for complete inactivation. Z. rouxii could be sterilized at 20 MPa and 26. A comparison of the continuous and batch method showed that L. brevis was inactivated completely under pressured CO 2 Ͼ0.16 g/ cm 3 with the continuous method and Ͼ0.9 g/cm 3 with the batch method.
Volatile compounds in fish sauce were isolated by a column concentration
method using Porapak Q
and by a simultaneous distillation and extraction method with diethyl
ether under reduced pressure.
Column concentration isolates were further fractionated by silica
gel column chromatography and
organoleptically evaluated. About 155 volatile compounds,
including 14 acids, 36 carbonyls, 17
nitrogen-containing compounds, and 10 sulfur-containing compounds, were
identified. Column
concentration could be a suitable method for isolating volatile
compounds in fish sauce. Large
amounts of acids, large numbers of carbonyls and sulfur-containing
compounds, such as, dimethyl
sulfide, dimethyl trisulfide, and 3-(methylthio)propanal, as well
as many types of nitrogen-containing
compounds are thought to be major contributors to fish sauce
odor.
Keywords: Fish sauce; odor; volatile compounds
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