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1.
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   

2.
The volatile compounds of salmon fillets smoked according to four smoked generation techniques (smoldering, thermostated plates, friction, and liquid smoke) were investigated. The main odor-active compounds were identified by gas chromatography coupled with olfactometry and mass spectrometry. Only the odorant volatile compounds detected by at least six judges (out of eight) were identified as potent odorants. Phenolic compounds and guaiacol derivatives were the most detected compounds in the olfactometric profile whatever the smoking process and could constitute the smoky odorant skeleton of these products. They were recovered in the aromatic extracts of salmon smoked by smoldering and by friction, which were characterized by 18 and 25 odor-active compounds, respectively. Furannic compounds were more detected in products smoked with thermostated plates characterized by 26 odorants compounds. Finally, the 27 odorants of products treated with liquid smoke were significantly different from the three others techniques applying wood pyrolysis because pyridine derivatives and lipid oxidation products were perceived in the aroma profile.  相似文献   

3.
The aroma compounds present in cooked brown rice of the three varieties Improved Malagkit Sungsong (IMS), Basmati 370 (B 370), and Khaskhani (KK), and of the variety Indica (German supermarket sample), were identified on the basis of aroma extract dilution analyses (AEDA). A total of 41 odor-active compounds were identified, of which eleven are reported for the first time as rice constituents. 2-Amino acetophenone (medicinal, phenolic), which was up to now unknown in rice aroma, exhibited the highest flavor dilution (FD) factor among the 30 to 39 odor-active compounds detected in all four varieties. 2-Acetyl-1-pyrroline, exhibiting an intense popcorn-like aroma-note, was confirmed as a further key aroma constituent in IMS, B 370, and KK, but was not important in Indica. Differences in the FD factors between the varieties were found for the previously unknown rice aroma compound 3-hydroxy-4,5-dimethyl-2(5H)-furanone (Sotolon; seasoning-like), which was higher in B 370 than in IMS and KK. In IMS, a yet unknown, spicy smelling component with a very high FD factor could be detected, which contributed with lower FD factors to the overall aromas of B 370 and KK, and was not present in Indica. The latter variety, which was available on the German market, differed most in its overall aroma from the three Asian brown rices.  相似文献   

4.
Volatile compounds emanating from three cultivars of cooked rice milled to different degrees (0, 8, and 30% by weight) were compared to ascertain their site of origin and the effect of pigmentation on synthesis. The cultivars tested were Ilpumbyeo (traditional white rice), Heugjinjubyeo (black pigmented), and Jeogjinjubyeo (red pigmented). In total, 29, 38, and 27 volatile compounds were identified in dehulled, unmilled Ilpumbyeo, Heugjinjubyeo, and Jeogjinjubyeo, respectively. Significant quantitative and qualitative differences were found among the cultivars in their volatile profiles. 2‐Acetyl‐1‐pyrroline, guaiacol, 1‐nonanol, 3‐octen‐2‐one, 1,2‐dimethoxybenzene, pyridine, and pyrrole were found only in Heugjinjubyeo and phenylacetaldehyde only in Jeogjinjubyeo. Removal of the bran, partial endosperm, and pigment qualitatively and quantitatively affected the volatile compounds formed, with certain volatiles higher in unmilled rice (0% milling), indicating the pericarp and aleurone layer (bran) as their primary site of origin. Volatiles emanating from the 8 and 30% milled samples indicated the outer and middle endosperm (8%) and core endosperm (30%) as the primary sites of origin. Therefore, differences in chemical composition with location within the grain appear to account for the quantitative and qualitative variation in volatile synthesis.  相似文献   

5.
6.
By application of the aroma extract dilution analysis on the volatile fraction isolated from a black tea infusion (Darjeeling Gold Selection), vanillin (vanilla-like), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (caramel), 2-phenylethanol (flowery), and (E,E,Z)-2,4,6-nonatrienal (oat-flake-like) were identified with the highest flavor dilution (FD) factors among the 24 odor-active compounds detected in the FD factor range of 4-128. Quantitative measurements performed by means of stable isotope dilution assays and a calculation of odor activity values (OAVs; ratio of concentration to odor threshold in water) revealed, in particular, the previously unknown tea constituent (E,E,Z)-2,4,6-nonatrienal as a key odorant in the infusion and confirmed the important role of linalool and geraniol for the tea aroma. An aroma recombinate performed by the 18 odorants for which OAVs > 1 were determined in their "natural" concentrations matched the overall aroma of the tea beverage. In the black tea leaves, a total of 42 odorants were identified, most of which were identical with those in the beverage prepared thereof. However, quantitative measurements indicated that, in particular, geraniol, but also eight further odorants were significantly increased in the infusion as compared to their concentration in the leaves.  相似文献   

7.
Volatile compounds of cooked rice from scented (Aychade, Fidji) and nonscented (Ruille) cultivars grown in the Camargue area in France were compared to that of a marketed Asian scented one (Thai) by gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). GC-O analyses of the organic extracts resulted in the perception of 40 odorous compounds. Only two compounds, oct-1-en-3-one and 2-acetyl-1-pyrroline, were almost always perceived. Hierarchical cluster analysis showed that most of the difference between rice odors was linked to quantitative differences with only 11 compounds being specific to some of the rice. Sixty compounds were identified and quantified by GC-MS, including a few new odor-active components. Principal component analysis enabled us to differentiate scented cultivars from a nonscented one, and scented rice cultivars from Camargue from a Thai sample. Calculated odor-active values evidenced that the Thai sample odor differed from that of scented Camargue cultivars because of the degradation of lipids and of cinnamic acid compounds.  相似文献   

8.
Heat processing during canning is responsible for the change in flavor of black tea infusion. The quantitative change in the volatile components of the black tea infusion during heat processing is not sufficient for explaining the sensory evaluation. In this study, application of aroma extract dilution analysis using the volatile fraction before and after black tea (Darjeeling) samples were heat processed resulted in the detection of 10 odor-active peaks for which flavor dilution (FD) factors changed. Seven potent odorants were identified from these peaks by gas chromatography-mass spectrometry. Among these components, 3-methylbutanal (stimulus), methional (potato-like), beta-damascenone (sweet), dimethyl trisulfide (putrid), and 2-methoxy-4-vinylphenol (clove-like) showed the highest FD factors after heat processing of the black tea sample. Therefore, these odorants were the most important components involved in changing the black tea odor during heat processing. In addition, the precursor of beta-damascenone in black tea infusion was investigated, and 3-hydroxy-7,8-didehydro-beta-ionol was determined to be one of the beta-damascenone-generating compounds for the first time.  相似文献   

9.
Sensory evaluation was used to identify flavor precursors that are critical for flavor development in cooked chicken. Among the potential flavor precursors studied (thiamin, inosine 5'-monophosphate, ribose, ribose-5-phosphate, glucose, and glucose-6-phosphate), ribose appears most important for chicken aroma. An elevated concentration (added or natural) of only 2-4-fold the natural concentration gives an increase in the selected aroma and flavor attributes of cooked chicken meat. Assessment of the volatile odor compounds by gas chromatography-odor assessment and gas chromatography-mass spectrometry showed that ribose increased odors described as "roasted" and "chicken" and that the changes in odor due to additional ribose are probably caused by elevated concentrations of compounds such as 2-furanmethanethiol, 2-methyl-3-furanthiol, and 3-methylthiopropanal.  相似文献   

10.
The volatile components of Hyuganatsu (Citrus tamurana Hort. ex Tanaka) peel oil, isolated by cold-pressing, were investigated by chemical and sensory analyses. According to chemical analysis by GC and GC-MS, limonene (84.0%) was the most abundant compound, followed by gamma-terpinene (6.9%), myrcene (2.2%), alpha-pinene (1.2%), and linalool (1.0%). Monoterpene hydrocarbons were predominant in Hyuganatsu peel oil. The odor-active volatiles in Hyuganatsu flavor were studied by GC-olfactometry and omission tests. The characteristic flavor was present in the oxygenated fraction. Flavor dilution (FD) factors of the volatile flavor components of the Hyuganatsu cold-pressed oil were determined by aroma extraction dilution analysis (AEDA). Furthermore, relative flavor activity was investigated by means of FD factor and weight percent. Ten kinds of odor compounds having Hyuganatsu-like aroma were detected by AEDA: limonene, linalool, octanol, neral, neryl acetate, tridecanal, trans-carveol, cis-nerolidol, trans,trans-farnesyl acetate, and trans,trans-farnesol. Linalool and octanol were regarded as the most odor-active or key compounds of Hyuganatsu aroma. Diluted solutions of linalool and octanol of approximately 2 ppm gave a fresh and fruity aroma note similar to Hyuganatsu flavor.  相似文献   

11.
The major volatile constituents of lapsang souchong, smoked lapsang souchong, and smoked souchong, a group of special black teas in China, were analyzed with GC and GC-MS analyses. Forty-nine constituents were identified. Longifolene and alpha-terpineol were the most abundant compounds in the aroma. Due to its special production process, the compounds longifolene, longicyclene, guaiacol, 4-methylguaiacol, 4-ethylguaiacol, etc., were identified only in this kind of black tea. The aroma constituents of tea origin decreased during the smoking process, whereas the pine terpenoids and the thermal pyrolysis products of the pine wood increased markedly. The pine material for smoking was also analyzed for the volatile constituents showing apparent selectivity of the tea leaves to absorb. There were apparent differences among the tea samples in the contents of aroma constituents. The characteristics of the aroma of the teas are discussed with their processes and the features of sensory qualities.  相似文献   

12.
茶叶加工对茶叶香气的形成至关重要。为了研究黄大茶加工过程中香气成分的组成及变化规律,采用气相色谱-离子迁移谱(Gas Chromatography-Ion Mobility Spectrometry,GC-IMS)技术对黄大茶加工过程的挥发性成分进行分析。定性分析、鉴定茶叶挥发性成分,构建黄大茶加工过程挥发性成分的差异谱图,并以鉴定的挥发性成分对黄大茶加工过程进行主成分分析。共鉴定出挥发性成分40种,主要有醇类、酮类、醛类、酯类和杂环类化合物。杂环类和醛类化合物是黄大茶挥发性成分的主体部分,且杀青之后,杂环类化合物的含量随着加工过程的进行逐渐增加,醛类化合物的相对含量在初烘之后呈现显著性增加,而醇类及酮类挥发性成分的相对含量在初烘之后显著性降低(P0.05)。具花香的氧化芳樟醇只在初闷之前的样品中得到鉴定,在鲜叶中的含量最高,达21.98%,而1-辛烯-3-酮及苯乙酮只在初烘之后的样品中得到鉴定。通过GC-IMS的指纹图谱可知,苯甲醛、2,5-二甲基呋喃、糠醛及二甲基二硫等挥发性成分构成了经"拉老火"工序的黄大茶的特征峰区域。在一定程度上,主成分分析能够将黄大茶加工过程样品进行区分,表明气相色谱-离子迁移谱分析可为黄大茶加工过程的判别区分提供可能。相较于传统的茶叶挥发性成分检测分析技术,气相色谱-离子迁移谱具有快速、高效、绿色环保的特点。研究结果提供一种新的茶叶挥发性成分的检测分析方法,同时为茶叶加工过程监测及品质控制等提供了一定参考依据和理论基础。  相似文献   

13.
Isolation of the volatile fraction from cocoa powder (50 g; 20% fat content) by a careful extraction/distillation process followed by application of an aroma extract dilution analysis revealed 35 odor-active constituents in the flavor dilution (FD) factor range of 8-4096. Among them, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (caramel-like), 2- and 3-methylbutanoic acid (sweaty, rancid), dimethyl trisulfide (cooked cabbage), 2-ethyl-3,5-dimethylpyrazine (potato-chip-like), and phenylacetaldehyde (honey-like) showed the highest FD factors. Quantitation of 31 key odorants by means of stable isotope dilution assays, followed by a calculation of their odor activity values (OAVs) (ratio of concentration to odor threshold) revealed OAVs>100 for the five odorants acetic acid (sour), 3-methylbutanal (malty), 3-methylbutanoic acid, phenylacetaldehyde, and 2-methylbutanal (malty). In addition, another 19 aroma compounds showed OAVs>1. To establish their contribution to the overall aroma of the cocoa powder, these 24 compounds were added to a reconstructed cocoa matrix in exactly the same concentrations as they occurred in the cocoa powder. The matrix was prepared from deodorized cocoa powder, which was adjusted to 20% fat content using deodorized cocoa butter. The overall sensory evaluation of this aroma recombinate versus the cocoa powder clearly indicated that the 24 compounds represented the typical sweet, cocoa-like odor of the real sample.  相似文献   

14.
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   

15.
The volatile compounds of guava wine were isolated by continuous solvent extraction and analyzed by GC-FID and GC-MS. A total of 124 volatile constituents were detected, and 102 of them were positively identified. The composition of guava wine included 52 esters, 24 alcohols, 11 ketones, 7 acids, 6 aldehydes, 6 terpenes, 4 phenols and derivatives, 4 lactones, 4 sulfur-compounds, and 5 miscellaneous compounds. The aroma-active areas in the gas chromatogram were screened by application of the aroma extract dilution analysis and by odor activity values. Twelve odorants were considered as odor-active volatiles: (E)-β-damascenone, ethyl octanoate, ethyl 3-phenylpropanoate, ethyl hexanoate, 3-methylbutyl acetate, 2-methyltetrahydrothiophen-3-one, 2,5-dimethyl-4-methoxy-3(2H)-furanone, ethyl (E)-cinnamate, ethyl butanoate, (E)-cinnamyl acetate, 3-phenylpropyl acetate, and ethyl 2-methylpropanoate.  相似文献   

16.
The purpose of this study was to understand why some canned orange juices are not perceived as orange juice. Sensory flavor profile data indicated that the primary odor (orthonasal) attributes were tropical fruit/grapefruit, cooked/caramel, musty, and medicine. By comparison fresh-squeezed juice lacked these odor attributes. GC-O analysis found 43 odor-active components in canned juices. Eight of these aroma volatiles were sulfur based. Four of the 12 most intense aroma peaks were sulfur compounds that included methanethiol, 1-p-menth-1-ene-8-thiol, 2-methyl-3-furanthiol, and dimethyl trisulfide. The other most intense odorants included 7-methyl-3-methylene-1,6-octadiene (myrcene), octanal, 2-methoxyphenol (guaiacol), 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone (homofuraneol), (E)-non-2-enal, (E,E)-deca-2,4-dienal, 4-hydroxy-3-methoxybenzaldehyde (vanillin), and alpha-sinensal. Odorants probably responsible for the undesirable sensory attributes included grapefruit (1-p-menth-1-ene-8-thiol), cooked [2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (Furaneol), and 3-(methylthio)propanal (methional)], musty [7-methyl-3-methylene-1,6-octadiene and (E)-non-2-enal], and medicine (2-methoxyphenol). The canned juices also lacked several aldehydes and esters normally found in fresh orange juice.  相似文献   

17.
不同品种鲜食糯玉米清汁与籽粒中挥发性成分比较   总被引:1,自引:0,他引:1  
为研究不同品种鲜食糯玉米香气成分之间的差异,本研究对6个品种糯玉米进行了清汁制作和煮制两种熟化生香处理,并采用顶空固相微萃取法结合气相色谱-质谱联用技术(HS-SPME-GC-MS)对其挥发性成分进行测定。结果表明,清汁中检出的挥发性成分数量和总量均高于籽粒:清汁中检出38种挥发性成分,熟粒中检出24种,其中仅在清汁中检出的成分中有7种为吡嗪类化合物;而各品种糯玉米清汁中检测到的挥发性成分总量是籽粒的3.98~10.92倍。主成分分析(PCA)结果显示,前两个主成分可解释清汁样品总方差的72.6%,高于煮制籽粒(60.9%),但两种PCA结果均显示JDN-517、SYN-602与SYN-11的特色值得关注,并与吡嗪以及醛醇类成分含量差异有关。本研究结果为不同品种鲜食糯玉米风味品质评价中的样品处理以及数据分析提供了一定的参考。  相似文献   

18.
Solid phase microextraction (SPME) is used to collect and concentrate the compounds in the headspace of rice. This research describes optimization parameters of temperature, moisture, and sampling time. Optimization was based upon the recovered levels of 2-acetyl-1-pyrroline (2-AP), the popcorn aroma in aromatic rice. The method uses a sampling temperature of 80 degrees C and adds 100 microL of water to a 0.75 g sample of rice. The rice was preheated for 25 min, a carboxen/DVB/PDMS SPME fiber was exposed to the headspace for 15 min, and a subsequent GC-MS analysis took 35 min. Samples of rice can be analyzed as the flour, milled kernels, or brown rice. Twenty-one experimental rice varieties were analyzed by the SPME method and compared to a wet technique. Recoveries of several nanograms of 2-AP from 0.75 g samples of aromatic rice were observed, whereas only trace amounts of 2-AP were recovered from nonaromatic rice. Recovery from a single SPME headspace analysis is calculated to be 0.3% of the total 2-AP in the sample.  相似文献   

19.
20.
The odor-active compounds of dry-fermented sausages with added nitrite or nitrate as curing agents were identified by gas chromatography-olfactometry (GC-O) applying the detection frequency (DF) method. The quantification of these compounds in the sausage was determined by multiple headspace solid-phase microextraction (multiple HS-SPME). There were no specific odor-active compounds related to the use of nitrite or nitrate although there were differences in the DF value of several compounds. The nitrite-added sausages presented higher DF values for ethanol, 1-hexanol, propanoic acid, 2-heptenal, and nonanal while the nitrate-added sausages had higher DF values for phenylacetaldehyde and 3-methyl-butanal. Eighteen compounds were quantified by multiple HS-SPME. Most of them were above their air detection thresholds, but only hexanal, heptanal, and 1-octen-3-ol were in a concentration higher than their oil threshold values. These compounds would probably be the main contributors to the aroma of fermented sausages.  相似文献   

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