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1.
To identify the component(s) causing the foxy odor, characteristic for some Fritillaria imperialis cultivars, the headspace of flower bulbs was analyzed using gas chromatography-olfactometry (GC-O) and GC-mass spectrometry (GC-MS). Six Fritillaria species and cultivars were selected as follows: F. imperialis cv. Premier (very strong foxy odor), F. imperialis cv. Lutea (strong foxy odor), F. imperialis ssp. Inodora (no odor), Fritillaria eduardii (weak mousy odor), Fritillaria raddeana (no odor), and an F1 of F. imperialis Lutea x Inodora (weak foxy odor). Volatiles from these flower bulbs were accumulated on Tenax and injected into the GC by thermodesorption. The majority of the volatiles consisted of low molecular weight aliphatic compounds. GC-O revealed that the foxy odor was caused by a single component, identified as 3-methyl-2-butene-1-thiol on the basis of smell in GC-O analyses (two GC columns), mass spectra, and retention times. Chemical identification was substantiated by GC-O and GC-MS of an authentic standard of 3-methyl-2-butene-1-thiol, prepared by organic synthesis.  相似文献   

2.
Characterization of the flavors of ripened roe products is of importance to establish a basis for a standardized product. Flavor profiles of commercially processed ripened roe from Iceland and Norway were studied by sensory analysis, gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS), and an electronic nose to characterize the headspace of ripened roe. Sensory analysis showed that ripened roe odor and flavor in combination with caviar flavor and whey/caramel-like odor give the overall positive effect of the complex characteristic roe flavor. Analysis of volatiles by GC-MS and electronic nose confirmed the presence of aroma compounds contributing to the typical ripening and spoilage flavors detected by the sensory analysis. Methional, 1-octen-3-ol, and 2,6-nonadienal were the most important compounds contributing to ripened roe odor. Spoilage flavors were partly contributed by 3-methyl-1-butanol and 3-methylbutanal, which can be measured by the electronic nose and are suggested as quality indicators for objectively assessing the ripening of roe. Principal component analysis of the overall data showed that GC-O correlated well with sensory evaluation and the electronic nose measurements.  相似文献   

3.
Fifty volatile compounds of surface smear-ripened cheese were detected and identified using headspace solid-phase microextraction (HS-SPME) and vacuum distillation coupled to gas chromatography-mass spectrometry. Changes in the headspace of aroma compounds were monitored over the whole packaging period (47 days) using the HS-SPME method. Initially, the concentration of methanethiol increased before reaching a plateau. This evolution could be linked to the growth of Brevibacterium linens. During the shelf life of cheese, levels of acetic acid and 3-methylbutanoic acid remained constant, whereas butane-2,3-dione, 3-hydroxybutan-2-one, and hydroxypropan-2-one levels gradually declined and acetone and 3-methylbutanol levels dropped sharply to a plateau. Changes in odor could be related to changes of the rind, which behaved as a barrier, strongly influencing the distribution of volatile compounds in the headspace. Using a gas chromatography-olfactometry technique without separation, it was shown that the SPME extract was representative of the cheese odor.  相似文献   

4.
The sensorial quality of solid phase microextraction (SPME) flavor extracts from orange juice was measured by direct gas chromatogrphy-olfactometry (D-GC-O), a novel instrumental tool for evaluating odors from headspace extracts. In general, odor impressions emerging from SPME extracts poorly resembled that of the original orange juice. In an attempt to improve the sensorial quality of extracts, sample equilibration and exposure times were varied on Carboxen/polydimethylsiloxane (CAR/PDMS) and divinylbenzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) SPME fibers. Best sensorial results were obtained with the DVB/CAR/PDMS fiber exposed for the shortest time; a trained panel of eight assessors judged its odor as the most representative of the reference orange juice. The analysis of odor active compounds by classical GC-O accounted for odor characteristics revealed by D-GC-O. A principal component analysis (PCA) was applied on SPME and headspace extracts using flavor recoveries as variables. Interestingly, PCA discriminated samples according to their odor representations described by D-GC-O analysis. This paper provides the first comprehensive methodology to "smell" SPME extracts and "evaluate" their sensorial quality. This method will enable future investigations to further improve SPME performance.  相似文献   

5.
Volatiles of a wild mandarin, Mangshanyegan (Citrus nobilis Lauriro), were characterized by GC-MS, and their aroma active compounds were identified by aroma extract dilution analysis (AEDA) and gas chromatography-olfactometry (GC-O). The volatile profile of Mangshanyegan was compared with those of other four citrus species, Kaopan pummelo (Citrus grandis), Eureka lemon (Citrus limon), Huangyanbendizao tangerine (Citrus reticulata), and Seike navel orange (Citrus sinensis). Monoterpene hydrocarbons predominated in Mangshanyegan, in particular d-limonene and β-myrcene, which accounted for 85.75 and 10.89% of total volatiles, respectively. Among the 12 compounds with flavor dilution factors (FD) = 27, 8 oxygenated compounds, including (Z)- and (E)-linalool oxides, were present only in Mangshanyegan. The combined results of GC-O, quantitative analysis, odor activity values (OAVs), and omission tests revealed that β-myrcene and (Z)- and (E)-linalool oxides were the characteristic aroma compounds of Mangshanyegan, contributing to the balsamic and floral notes of its aroma.  相似文献   

6.
The unique flavor of Oscypek, a Polish ewe's milk smoked cheese, is described as slightly sour, piquant, salted, and smoked. In this paper with the application of gas chromatography-olfactometry (GC-O) and combination of aroma extract dilution analysis (AEDA) 20 potent odorants of this cheese have been identified within the flavor dilution factor (FD) range of 4-2048. Among them, 2-methoxyphenol, 2-methoxy-4-methylphenol, 4-methylphenol, and butanoic acid showed the highest FD factors. Quantification results based on labeled standard addition followed by calculation of odor activity values (OAV) of 13 compounds with the highest FD factors revealed that 11 compounds were present at concentrations above their odor threshold values and therefore mostly contribute to the overall aroma of smoked ewe's milk cheese. Six of those compounds were represented by phenolic derivatives, with the highest OAV for 2-methoxyphenol (1280). Analysis of key odorants of an unsmoked cheese sample showed that the smoking process had a fundamental influence on Oscypek aroma formation.  相似文献   

7.
This work focused on developing a method to determine the volatile compounds that contribute to individual masses observed by PTR-MS in the headspace of a food product (e.g., cheese crackers). The process of interfacing a PTR-MS with a GC-MS (electron impact) through an existing sniffing port is outlined, and the problems faced in doing so are discussed. For the interface developed, linearity for both detectors working online for a wide range of concentrations of a selected compound (hexanal) was good (R(2) = 0.88). There was also a good correlation between the responses for both instruments (confidence interval for the slope between 0.56 and 1.18) over a range in concentrations despite the different ionization processes taking place. The application of our system (PTR-MS/GC-MS interface) to a real food system (cheese crackers) in which volatiles were isolated via purge and trap allowed the assignments of most of the PTR-MS masses to major volatile compounds in the samples. However, in this interface it is important to consider some limitations related to GC resolution, compound identification by EI-MS, PTR-MS sensitivity (and overloading), PTR-MS inlet requirements (ca. 20 mL/min), ion chemistry in the PTR-MS, and potentially changing sample composition over time, altering the contribution of a given compound to a specific ion. These issues are discussed.  相似文献   

8.
Odorant compounds of five young clonal red wines made from cv. Trincadeira, a native grape variety of Vitis vinifera L. grown in Portugal, were studied using 2001 and 2003 vintages. The study was carried out using gas chromatography-mass spectrometry (GC-MS) for compound identification and the gas chromatography-olfactometry (GC-O) posterior intensity method to detect the potentially most important aroma compounds. Forty-one odorant peaks were detected by GC-O analysis, from which 31 were identified by GC-MS. The odorant compounds with the highest odorant average intensities are 3-methylbutanoic acid, 2-phenylethanol, 2,5-dimethyl-4-hydroxy-3(2H)-furanone, and 4-vinylguaiacol. The GC-O analysis showed odor intensity differences among compounds, which was confirmed by analysis of variance (ANOVA). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed that the five clonal wines from the 2001 vintage were more similar than those from the 2003 vintage. Moreover, stepwise linear discriminant analysis (SLDA) demonstrated that the factor vintage has influence on the Trincadeira clonal red wine odorant profile differentiation.  相似文献   

9.
Key aroma components of cooked tail meat of American lobster (Homarus americanus) were studied by gas chromatography-olfactometry (GCO) techniques. Components of low and intermediate volatility were evaluated by aroma extract dilution analysis of solvent extracts prepared by direct solvent extraction-high vacuum distillation and vacuum steam distillation-solvent extraction, whereas headspace volatile components were assessed by GCO of decreasing headspace (static and dynamic modes) samples. Forty-seven odorants were detected by all techniques. 3-Methylbutanal (chocolate, malty), 2,3-butanedione (buttery), 3-(methylthio)propanal (cooked potato), 1-octen-3-one (mushroom), 2-acetyl-1-pyrroline (popcorn), and (E,Z)-2,6-nonadienal (cucumber), were identified as predominant odorants by all four isolation methods. The highly volatile compounds methanethiol (rotten, sulfurous) and dimethyl sulfide (canned corn) were detected by headspace methods only. These eight odorants along with three unknown compounds with crabby, amine, fishy odors were found to predominate in the overall aroma of cooked lobster tail meat.  相似文献   

10.
This study was conducted to determine the composition of kumquat (Fortunella japonica Swingle) cold-pressed peel oil and to determine which volatile components are primarily responsible for the aroma of this oil. Eighty-two compounds were identified in the oil by GC and GC-MS. The major compounds were limonene (93.73%), myrcene (1.84%), and ethyl acetate (1.13%). Flavor dilution (FD) factors and relative flavor activities (RFA) of volatile constituents were evaluated by aroma extract dilution analysis with gas chromatography-olfactometry (GC-O). Camphene, terpinen-4-ol, citronellyl formate, and citronellyl acetate showed high FD factors (>/=5) and RFA (>20). Citronellyl formate and citronellyl acetate were regarded as the characteristic odor components of the kumquat peel oil from the results of FD factor, RFA, and GC-sniffing. Citronellyl acetate is considered to be the odor component most similar to kumquat by organoleptic evaluation with GC-O.  相似文献   

11.
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12.
Volatile compounds of cooked fillets of Silurus glanis reared under two conditions occurring in France were studied. They were extracted by dynamic headspace, identified by gas chromatography/mass spectrometry, and quantified by gas chromatography-flame ionization detection. Odor active volatile compounds were characterized by gas chromatography-olfactometry. Sixty volatile compounds were detected in dynamic headspace extracts, among which 33 were odor active. Rearing conditions affected their estimated concentrations and their odor intensities, but very few qualitative differences were exhibited (only seven volatile compounds were concerned). A good correlation between quantitative and olfactometric results is shown. 2-Methylisoborneol and (E)-2-hexenal were less represented in OUTDOOR extracts, while 2-butanone was less represented in INDOOR extracts. In addition, olfactometric results can be closely related to those previously obtained by sensory analysis. Boiled potato sensory odor of the silurus cooked fillets can be related to (Z)-4-heptenal and methional, and buttery odor can be related to 2,3-butanedione, an unknown compound (RI = 1010), and 2,3-pentadione.  相似文献   

13.
Using a dynamic headspace system with Tenax trap, GC-MS, GC-olfactometry (GC-O), and multivariate analysis, the aroma chemistry of six distinctly different rice flavor types (basmati, jasmine, two Korean japonica cultivars, black rice, and a nonaromatic rice) was analyzed. A total of 36 odorants from cooked samples were characterized by trained assessors. Twenty-five odorants had an intermediate or greater intensity (odor intensity >or= 3) and were considered to be major odor-active compounds. Their odor thresholds in air were determined using GC-O. 2-Acetyl-1-pyrroline (2-AP) had the lowest odor threshold (0.02 ng/L) followed by 11 aldehydes (ranging from 0.09 to 3.1 ng/L), guaiacol (1.5 ng/L), and 1-octen-3-ol (2.7 ng/L). On the basis of odor thresholds and odor activity values (OAVs), the importance of each major odor-active compound was assessed. OAVs for 2-AP, hexanal, ( E)-2-nonenal, octanal, heptanal, and nonanal comprised >97% of the relative proportion of OAVs from each rice flavor type, even though the relative proportion varied among samples. Thirteen odor-active compounds [2-AP, hexanal, ( E)-2-nonenal, octanal, heptanal, nonanal, 1-octen-3-ol, ( E)-2-octenal, ( E, E)-2,4-nonadienal, 2-heptanone, ( E, E)-2,4-decadienal, decanal, and guaiacol] among the six flavor types were the primary compounds explaining the differences in aroma. Multivariate analysis demonstrated that the individual rice flavor types could be separated and characterized using these compounds, which may be of potential use in rice-breeding programs focusing on flavor.  相似文献   

14.
Freshness of ice-stored sardine was assessed by two sensory methods, the quality index method (QIM) and the European Union freshness grading system, and by instrumental means using the method of aroma extract dilution analysis. Screening of sardine potent volatiles was carried out at three freshness stages. In the very fresh state, the plant-like fresh volatiles dominated the odor pattern, with the exception of methional. Overall odor changes in sardine throughout storage correlated with changes in the concentration of some potent volatiles: after 2 days of ice storage, (Z)-4-heptenal, (Z)-1,5-octadien-3-one, and methional imparted an overall "fishy" odor character to sardine, whereas at a lower sensory grade (B), the compounds (E)-2-nonenal and (E,Z)-2,6-nonadienal could be, in part, associated with the slightly rancid aroma top notes. Trimethylamine was detected as a highly volatile odorant using solid-phase microextraction (SPME) headspace analysis of refrigerator-stored sardine. Intensity and sensory characteristics of some SPME determined volatiles, for example, 3-methylnonane-2,4-dione, were closely related to overall odor changes. SPME headspace analysis may be useful in the characterization of off-flavors in fish.  相似文献   

15.
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16.
Characterization of the most odor-active compounds of Iberian ham headspace   总被引：11，自引：0，他引：11  
Gas chromatography-olfactometry (GC-O) based on detection frequency (DF) was used to characterize the most odor-active compounds from the headspace of Iberian ham. Twenty-eight odorants were identified by GC-O on two capillary columns, including aldehydes (11), sulfur-containing compounds (7), ketones (5), nitrogen-containing compounds (2), esters (2), and an alcohol. Among them, the highest odor potencies (DF values) were found for 2-methyl-3-furanthiol, 2-heptanone, 3-methylbutanal, methanethiol, hexanal, hydrogen sulfide, 1-penten-3-one, 2-methylpropanal, ethyl 2-methylbutyrate, and (E)-2-hexenal. Nine of the 28 most odor-active compounds were identified for the first time as aroma components of dry-cured ham, including hydrogen sulfide, 1-penten-3-one, (Z)-3-hexenal, 1-octen-3-one, and the meaty-smelling compounds 2-methyl-3-furanthiol, 2-furfurylthiol, 3-mercapto-2-pentanone, 2-acetyl-1-pyrroline, and 2-propionyl-1-pyrroline.  相似文献   

17.
The influence of isolation method on the determination of important aroma compounds in black currant juice was investigated by surface of nasal impact frequency (SNIF) gas chromatography-olfactometry (GC-O). The applied methods were solvent extraction, static headspace, and purge and trap using 15 and 60 min of purge time. By the four methods, a total of 59 odors were observed, and, of these, 44 corresponded to compounds that could be identified. For the headspace methods increasing purge volumes resulted in recoveries of additional, less volatile compounds. The main compound groups recovered by the headspace methods were esters and terpenes, whereas compounds recovered by solvent extraction were not as dominated by fruity odors. For most compounds there was agreement between the size of the SNIF value obtained by GC-O and the amount of the measurable compound found by gas chromatography-mass spectrometry.  相似文献   

18.
The goal of this study was to better understand the correspondence between sensory perception and in-nose compound concentration. Five aroma compounds at three different concentrations increasing by factors of 4 were added to four matrixes (water, skim milk, 2.7% fat milk, and 3.8% fat milk). These were evaluated by nosespace analysis with detection by proton transfer reaction mass spectrometry (PTR-MS), using five panelists. These same panelists evaluated the perceived intensity of each compound in the matrixes at the three concentrations. PTR-MS quantification found that the percent released from an aqueous solution swallowed immediately was between 0.1 and 0.6%, depending on the compound. The nosespace and sensory results showed the expected effect of fat on release, where lipophilic compounds showed reductions in release as fat content increases. The effect is less than that observed in headspace studies. A general correlation between nosespace concentration and sensory intensity ratings was found. However, examples of perceptual masking were found where higher fat milks showed reductions in aroma compound intensity ratings, even if the nosespace concentrations were the same.  相似文献   

19.
The aroma-active compounds in two apple ciders were identified using gas chromatography-olfactometry (GC-O) and GC-mass spectrometry (MS) techniques. The volatile compounds were extracted using solvent-assisted flavor evaporation (SAFE) and headspace solid-phase microextraction (HS-SPME). On the basis of odor intensity, the most important aroma compounds in the two apple cider samples were 2-phenylethanol, butanoic acid, octanoic acid, 2-methylbutanoic acid, 2-phenylethyl acetate, ethyl 2-methylbutanoate, ethyl butanoate, ethyl hexanoate, 4-ethylguaiacol, eugenol, and 4-vinylphenol. Sulfur-containing compounds, terpene derivatives, and lactones were also detected in ciders. Although most of the aroma compounds were common in both ciders, the aroma intensities were different. Comparison of extraction techniques showed that the SAFE technique had a higher recovery for acids and hydroxy-containing compounds, whereas the HS-SPME technique had a higher recovery for esters and highly volatile compounds.  相似文献   

20.
Volatile organic compounds (VOCs) in fermented honeybush, Cyclopia subternata, were sampled by means of a high-capacity headspace sample enrichment probe (SEP) and analyzed by gas chromatography-mass spectrometry (GC-MS). Stereochemistry was determined by means of enantioselective GC-MS with derivatized β-cyclodextrin columns as chiral selectors. A total of 183 compounds, the majority of which are terpenoids (103; 56%), were identified by comparing their mass spectra and retention indices with those of reference compounds or tentatively identified by comparison with spectral library or literature data. Of these compounds, 37 were determined by gas chromatography-olfactometry (GC-O), using detection frequency (DF) and aroma extract dilution analysis (AEDA), to be odor-active (FD ≥ 2). (E)-β-Damascenone, (R/S)-linalool, (E)-β-damascone, geraniol, (E)-β-ionone, and (7E)-megastigma-5,7,9-trien-4-one were identified with the highest FD factors (≥512). The odors of certain compounds, that is, (6E,8Z)-megastigma-4,6,8-trien-3-one, (6E,8E)-megastigma-4,6,8-trien-3-one, (7E)-megastigma-5,7,9-trien-4-one, 10-epi-γ-eudesmol, epi-α-muurolol, and epi-α-cadinol, were perceived by GC-O assessors as typically honeybush-like.  相似文献   

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