The Experts below are selected from a list of 1062 Experts worldwide ranked by ideXlab platform

Peter Schieberle - One of the best experts on this subject based on the ideXlab platform.

  • quantitation and enantiomeric ratios of aroma compounds formed by an ehrlich degradation of l isoleucine in fermented foods
    Journal of Agricultural and Food Chemistry, 2016
    Co-Authors: Katrin Matheis, Michael Granvogl, Peter Schieberle
    Abstract:

    The conversion of parent free amino acids into alcohols by an enzymatic deamination, decarboxylation, and reduction caused by microbial enzymes was first reported more than 100 years ago and is today known as the Ehrlich pathway. Because the chiral center at the carbon bearing the methyl group in l-isoleucine should not be prone to racemization during the reaction steps, the analysis of the enantiomeric distribution in 2-Methylbutanal, 2-methylbutanol, and 2-methylbutanoic acid as well as in the compounds formed by secondary reactions, such as ethyl 2-methylbutanoate and 2-methylbutyl acetate, are an appropriate measure to follow the proposed degradation mechanism in the Ehrlich reaction. On the basis of a newly developed method for quantitation and chiral analysis, the enantiomers of the five metabolites were determined in a great number of fermented foods. Whereas 2-methylbutanol occurred as pure (S)-enantiomer in nearly all samples, a ratio of almost 1:1 of (S)- and (R)-2-Methylbutanal was found. These...

  • characterization of the aroma signature of styrian pumpkin seed oil cucurbita pepo subsp pepo var styriaca by molecular sensory science
    Journal of Agricultural and Food Chemistry, 2013
    Co-Authors: Susan Poehlmann, Peter Schieberle
    Abstract:

    Application of the aroma extract dilution analysis on a distillate prepared from an authentic Styrian pumpkin seed oil followed by identification experiments led to the characterization of 47 odor-active compounds in the flavor dilution (FD) factor range of 8-8192 among which 2-acetyl-1-pyrroline (roasty, popcorn-like), 2-propionyl-1-pyrroline (roasty, popcorn-like), 2-methoxy-4-vinylphenol (clove-like), and phenylacetaldehyde (honey-like) showed the highest FD factors. Among the set of key odorants, 2-propionyl-1-pyrroline and another 20 odorants were identified for the first time as constituents of pumpkin seed oil. To evaluate the aroma contribution in more detail, 31 aroma compounds showing the highest FD factors were quantitated by means of stable isotope dilution assays. On the basis of the quantitative data and odor thresholds determined in sunflower oil, odor activity values (OAV; ratio of concentration to odor threshold) were calculated, and 26 aroma compounds were found to have an OAV above 1. Among them, methanethiol (sulfury), 2-Methylbutanal (malty), 3-methylbutanal (malty), and 2,3-diethyl-5-methylpyrazine (roasted potato) reached the highest OAVs. Sensory evaluation of an aroma recombinate prepared by mixing the 31 key odorants in the concentrations as determined in the oil revealed that the aroma of Styrian pumpkin seed oil could be closely mimicked. Quantitation of 11 key odorants in three commercial pumpkin seed oil revealed clear differences in the concentrations of distinct odorants, which were correlated with the overall aroma profile of the oils.

  • changes in key aroma compounds of criollo cocoa beans during roasting
    Journal of Agricultural and Food Chemistry, 2008
    Co-Authors: Felix Frauendorfer, Peter Schieberle
    Abstract:

    Application of a comparative aroma extraction dilution analysis on unroasted and roasted Criollo cocoa beans revealed 42 aroma compounds in the flavor dilution (FD) factor range of 1-4096 for the unroasted and 4-8192 for the roasted cocoa beans. While the same compounds were present in the unroasted and roasted cocoa beans, respectively, these clearly differed in their intensity. For example, 2- and 3-methylbutanoic acid (rancid) and acetic acid (sour) showed the highest FD factors in the unroasted beans, while 3-methylbutanal (malty), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (caramel-like), and 2- and 3-methylbutanoic acid (sweaty) were detected with the highest FD factors in the roasted seeds. Quantitation of 30 odorants by means of stable isotope dilution assays followed by a calculation of odor activity values (ratio of the concentration/odor threshold) revealed concentrations above the odor threshold for 22 compounds in the unroasted and 27 compounds in the roasted cocoa beans, respectively. In particular, a strong increase in the concentrations of the Strecker aldehydes 3-methylbutanal and phenylacetaldehyde as well as 4-hydroxy-2,5-dimethyl-3(2H)-furanone was measured, suggesting that these odorants should contribute most to the changes in the overall aroma after roasting. Various compounds contributing to the aroma of roasted cocoa beans, such as 3-methylbutanoic acid, ethyl 2-methylbutanoate, and 2-phenylethanol, were already present in unroasted, fermented cocoa beans and were not increased during roasting.

  • characterization of the most odor active compounds in an american bourbon whisky by application of the aroma extract dilution analysis
    Journal of Agricultural and Food Chemistry, 2008
    Co-Authors: Luigi Poisson, Peter Schieberle
    Abstract:

    Application of the aroma extract dilution analysis (AEDA) on the volatile fraction carefully isolated from an American Bourbon whisky revealed 45 odor-active areas in the flavor dilution (FD) factor range of 32−4096 among which (E)-β-damascenone and δ-nonalactone showed the highest FD factors of 4096 and 2048, respectively. With FD factors of 1024, (3S,4S)-cis-whiskylactone, γ-decalactone, 4-allyl-2-methoxyphenol (eugenol), and 4-hydroxy-3-methoxy-benzaldehyde (vanillin) additionally contributed to the overall vanilla-like, fruity, and smoky aroma note of the spirit. Application of GC-Olfactometry on the headspace above the whisky revealed 23 aroma-active odorants among which 3-methylbutanal, ethanol, and 2-Methylbutanal were identified as additional important aroma compounds. Compared to published data on volatile constituents in whisky, besides ranking the whisky odorants on the basis of their odor potency, 13 aroma compounds were newly identified in this study: ethyl (S)-2-methylbutanoate, (E)-2-hepten...

  • characterization of the key aroma compounds in soy sauce using approaches of molecular sensory science
    Journal of Agricultural and Food Chemistry, 2007
    Co-Authors: Petra Steinhaus, Peter Schieberle
    Abstract:

    Application of aroma extract dilution analysis (AEDA) to the volatiles isolated from a commercial Japanese soy sauce revealed 30 odor-active compounds in the flavor dilution (FD) factor range of 8-4096, among which 2-phenylethanol showed the highest FD factor of 4096, followed by 3-(methylsulfanyl)propanal (methional), the tautomers 4-hydroxy-5-ethyl-2-methyl- and 4-hydroxy-2-ethyl-5-methyl-3(2H)-furanone (4-HEMF), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (4-HDF), and 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolone), all showing FD factors of 1024. Thirteen odorants were quantified by stable isotope dilution assays, and their odor activity values (OAVs) were calculated as ratio of their concentrations and odor thresholds in water. Among them, 3-methylbutanal (malty), sotolone (seasoning-like), 4-HEMF (caramel-like), 2-Methylbutanal (malty), methional (cooked potato), ethanol (alcoholic), and ethyl 2-methylpropanoate (fruity) showed the highest OAVs (>200). An aqueous model aroma mixture containing 13 odorants, which had been identified with the highest OAVs, in concentrations that occur in the soy sauce showed a good similarity with the overall aroma of the soy sauce itself. Heat treatment of the soy sauce resulted in a clear change of the overall aroma. Quantitation of selected odorants revealed a significant decrease in sotolone and, in particular, increases in 2-acetyl-1-pyrroline, 4-HDMF, and 4-HEMF induced by heating.

Michael C. Qian - One of the best experts on this subject based on the ideXlab platform.

  • quantitative determination of thermally derived off flavor compounds in milk using solid phase microextraction and gas chromatography
    Journal of Dairy Science, 2005
    Co-Authors: P A Vazquezlandaverde, Gonzalo Velazquez, J A Torres, Michael C. Qian
    Abstract:

    Many volatile compounds generated during the thermal processing of milk have been associated with cooked, stale, and sulfurous notes in milk and are considered as off-flavor by most consumers. A headspace solid-phase microextraction (HS-SPME)/gas chromatographic technique for the quantitative analysis of thermally derived off-flavor compounds was developed in this study. The extraction temperature, time, and sample amount were optimized using a randomized 2(3) central composite rotatable design with 2 central replicates and 2 replicates in each factorial point along with response surface methodology. Calibration curves were constructed in milk using the standard addition technique, and then used to quantify 20 off-flavor compounds in raw, pasteurized, and UHT milk samples with various fat contents. The concentrations of these volatiles in raw and pasteurized milk samples were not significantly different. However, dimethyl sulfide, 2-hexanone, 2-heptanone, 2-nonanone, 2-undecanone, 2-methylpropanal, 3-methylbutanal, heptanal, and decanal were found at higher concentrations in UHT milk as compared with raw and pasteurized milk samples. In addition, the concentration of methyl ketones was greater in UHT milk with higher fat content. The calculated odor activity values suggested that 2,3-butanedione, 2-heptanone, 2-nonanone, 2-methylpropanal, 3-methylbutanal, nonanal, decanal, and dimethyl sulfide could be important contributors to the off-flavor of UHT milk. The HS-SPME technique developed in this study is accurate and relatively simple, and can be used for the quantification of thermally derived off-flavor compounds in milk.

  • seasonal variation of volatile composition and odor activity value of marion rubus spp hyb and thornless evergreen r laciniatus l blackberries
    Journal of Food Science, 2005
    Co-Authors: Michael C. Qian, Yuanyuan Wang
    Abstract:

    Volatile compositions of 'Marion' and 'Thornless Evergreen' blackberries from 3 growing seasons were analyzed using gas chromatography-flame ionization detection (GC-FID) and GC-mass spectrometry (GC-MS). Although seasonal variations were present for both cultivars, it was generally observed that the most abundant volatiles in 'Marion' blackberry were acetic, 2/3-methylbutanoic, hexanoic and decanoic acids, ethanol, and linalool, whereas the most abundant volatiles in 'Thornless Evergreen' were 2-heptanol, hexanol, octanol, α-pinene, nopol, and p-cymen-8-ol. Compared with 'Marion,' 'Thornless Evergreen' contained significantly more total volatiles, especially in alcohols, terpenoids, and phenols, whereas 'Marion' contained more organic acids. Odor activity values (OAVs) were determined to identify each cultivar's most potent odorants. The compounds with the high odor activity values (OAV > 10) in 'Marion' were ethyl hexanoate, β-ionone, linalool, 2-heptanone, 2-undecanone, α-ionone, and hexanal. The compounds with the high odor activity values (OAV > 10) in 'Thornless Evergreen' were ethyl hexanoate, 2-heptanone, ethyl 2-methylbutanoate, 2-heptanol, 3-methylbutanal, α-pinene, limonene, p-cymene, linalool, t-2-hexenal, myrtenol, hexanal, 2-Methylbutanal, and sabinene.

  • potent aroma compounds in parmigiano reggiano cheese studied using a dynamic headspace purge trap method
    Flavour and Fragrance Journal, 2003
    Co-Authors: Michael C. Qian, Gary A. Reineccius
    Abstract:

    The aroma-active compounds potentially important to Parmigiano Reggiano cheese were studied using a dynamic headspace–gas chromatography–olfactometry (GC–O–DH) technique. The aroma contribution was evaluated by both Osme and AEDA technique. The Osme values were based on a 10 point scale, while the flavour dilution values of AEDA were obtained by sequentially reducing the sample size at a fixed purge gas volume. In general, aroma compounds with high Osme values also had high FD values. Among the aroma compounds identified in Parmigiano Reggiano cheese, acetaldehyde, 2-methylpropanal, 2-Methylbutanal, 3-methylbutanal, ethyl butanoate, ethyl hexanoate, ethyl octanoate, methional, dimethyl trisulphide, diacetyl, and 2,6-dimethylpyrazine were considered the most odour-potent. Copyright © 2003 John Wiley & Sons, Ltd.

  • Static headspace and Aroma Extract Dilution Analysis of Parmigiano Reggiano cheese
    Journal of Food Science, 2003
    Co-Authors: Michael C. Qian, Gary A. Reineccius
    Abstract:

    The aroma compounds in Parmigiano Reggiano cheese were studied with Aroma Extract Dilution Analysis (AEDA). Both static headspace and solvent extraction, high-vacuum distillation techniques were used to isolate aroma compounds. Thirty-six odor-active compounds had high flavor dilution values. Static headspace gas chromatography/olfactometry (GC/O) analysis found that acetaldehyde, 2-methylpropanal, 2-Methylbutanal, 3-methylbutanal, ethyl butanoaic, and ethyl hexanoate had low detection volumes, while high-vacuum distillation revealed that acetic, butanoic, hexanoic, octanoic, and decanoic acids, and ethyl butanoate, ethyl hexanoate, dimethyl trisulfide, methional, and phenylacetaldehyde had high flavor dilution values. In addition, some pyrazines appear to be important to the aroma of this cheese.

  • quantification of aroma compounds in parmigiano reggiano cheese by a dynamic headspace gas chromatography mass spectrometry technique and calculation of odor activity value
    Journal of Dairy Science, 2003
    Co-Authors: Michael C. Qian, Gary A. Reineccius
    Abstract:

    Potentially important aroma compounds in Parmigiano Reggiano cheese were quantified. Free fatty acids were isolated with ion-exchange chromatography and quantified by gas chromatography. Neutral aroma compounds were quantified with a purge-trap/gas chromatography-mass spectrometry with selective mass ion technique. Odor activity values were calculated based on sensory thresholds reported in literature. The calculated odor activity values suggest that 3-methylbutanal, 2-methylpropanal, 2-Methylbutanal, dimethyl trisulfide, diacetyl, methional, phenylacetaldehyde, ethyl butanoate, ethyl hexanoate, ethyl octanoate, acetic, butanoic, hexanoic, and octanoic acids are the most important aroma contributors to Parmigiano Reggiano cheese.

Zuo Bing Xiao - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of the key aroma compounds in Laoshan green teas by application of odour activity value (OAV), gas chromatography-mass spectrometry-olfactometry (GC-MS-O) and comprehensive two-dimensional gas chromatography mass spectrometry (GC × G
    Food chemistry, 2020
    Co-Authors: Jian Cai Zhu, Yun Wei Niu, Zuo Bing Xiao
    Abstract:

    Abstract To investigate the key aroma compounds in Laoshan green teas (Huangshan (S1), Changling (S2), and Fangling (S3)), gas chromatography-mass spectrometry-olfactometry (GC-MS-O), a flame photometric detector (FPD), odor activity value (OAV), and comprehensive two-dimensional gas chromatography mass spectrometry (GC × GC-qMS) were employed. A total of 50 aroma compounds were perceived and 24 compounds were identified as important compounds related to OAV, such as dimethyl sulfide (OAV: 126–146), skatole (OAV: 27–50), furaneol (OAV: 8–27), (Z)-jasmone (OAV: 16–23), 2-Methylbutanal (OAV: 15–22), and 3-methylbutanal (OAV: 68–87). Furthermore, the S-curve method was used to research the effect of aroma compounds on the threshold of aroma recombination (AR). The AR thresholds decreased from 3.8 mL to 0.45, 0.66, 0.93, 0.95, 0.75, 1.09, 3.01, and 2.57 mL after addition of eight compounds (skatole, furaneol, (Z)-jasmone, α-damascenone, sclareololide, dihydroactinidiolide, vanillin, and δ-valerolactone), indicating that those compounds (OAV >1) were contributors to the overall aroma of Laoshan teas.

  • Comparison of Aroma-Active Volatiles in Oolong Tea Infusions Using GC-Olfactometry, GC-FPD, and GC-MS
    Journal of Agricultural and Food Chemistry, 2015
    Co-Authors: Jian Cai Zhu, Ling Ying Wang, Yun Wei Niu, He Xing Chen, Hong Lin Wang, Chang Shu, Dan Yu, Feng Chen, Zuo Bing Xiao
    Abstract:

    The aroma profile of oolong tea infusions (Dongdingwulong, DDWL; Tieguanyin, TGY; Dahongpao, DHP) were investigated in this study. Gas chromatography-olfactometry (GC-O) with the method of aroma intensity (AI) was employed to investigate the aroma-active compounds in tea infusions. The results presented forty-three, forty-five, and forty-eight aroma-active compounds in the TGY, DHP, and DDWL infusions, including six, seven, and five sulfur compounds, respectively. In addition, the concentration of volatile compounds in the tea infusions was further quantitated by solid phase microextraction-gas chromatography (SPME)-GC-MS and SPME-GC-flame photometric detection (FPD). Totally, seventy-six and thirteen volatile and sulfur compounds were detected in three types of tea infusions, respectively. Quantitative results showed that forty-seven aroma compounds were at concentrations higher than their corresponding odor thresholds. On the basis of the odor activity values (OAVs), 2-methylpropanal (OAV: 230-455), 3-methylbutanal (1-353), 2-Methylbutanal (34-68), nerolidol (108-184), (E)-2-heptenal (148-294), hexanal (134-230), octanal (28-131), β-damascenone (29-59), indole (96-138), 6-methyl-5-hepten-2-one (34-67), (R)-(-)-linalool (63-87), and dimethyl sulfide (7-1320) presented relatively higher OAVs than those of other compounds, indicating the importance of these compounds in the overall aroma of tea infusions.

  • Comparison of Aroma-Active Volatiles in Oolong Tea Infusions Using GC–Olfactometry, GC–FPD, and GC–MS
    2015
    Co-Authors: Jian Cai Zhu, Ling Ying Wang, Yun Wei Niu, He Xing Chen, Hong Lin Wang, Chang Shu, Feng Chen, Zuo Bing Xiao
    Abstract:

    The aroma profile of oolong tea infusions (Dongdingwulong, DDWL; Tieguanyin, TGY; Dahongpao, DHP) were investigated in this study. Gas chromatography–olfactometry (GC–O) with the method of aroma intensity (AI) was employed to investigate the aroma-active compounds in tea infusions. The results presented forty-three, forty-five, and forty-eight aroma-active compounds in the TGY, DHP, and DDWL infusions, including six, seven, and five sulfur compounds, respectively. In addition, the concentration of volatile compounds in the tea infusions was further quantitated by solid phase microextraction–gas chromatography (SPME)–GC–MS and SPME–GC–flame photometric detection (FPD). Totally, seventy-six and thirteen volatile and sulfur compounds were detected in three types of tea infusions, respectively. Quantitative results showed that forty-seven aroma compounds were at concentrations higher than their corresponding odor thresholds. On the basis of the odor activity values (OAVs), 2-methylpropanal (OAV: 230–455), 3-methylbutanal (1–353), 2-Methylbutanal (34–68), nerolidol (108–184), (E)-2-heptenal (148–294), hexanal (134–230), octanal (28–131), β-damascenone (29–59), indole (96–138), 6-methyl-5-hepten-2-one (34–67), (R)-(−)-linalool (63–87), and dimethyl sulfide (7–1320) presented relatively higher OAVs than those of other compounds, indicating the importance of these compounds in the overall aroma of tea infusions

Gary A. Reineccius - One of the best experts on this subject based on the ideXlab platform.

  • potent aroma compounds in parmigiano reggiano cheese studied using a dynamic headspace purge trap method
    Flavour and Fragrance Journal, 2003
    Co-Authors: Michael C. Qian, Gary A. Reineccius
    Abstract:

    The aroma-active compounds potentially important to Parmigiano Reggiano cheese were studied using a dynamic headspace–gas chromatography–olfactometry (GC–O–DH) technique. The aroma contribution was evaluated by both Osme and AEDA technique. The Osme values were based on a 10 point scale, while the flavour dilution values of AEDA were obtained by sequentially reducing the sample size at a fixed purge gas volume. In general, aroma compounds with high Osme values also had high FD values. Among the aroma compounds identified in Parmigiano Reggiano cheese, acetaldehyde, 2-methylpropanal, 2-Methylbutanal, 3-methylbutanal, ethyl butanoate, ethyl hexanoate, ethyl octanoate, methional, dimethyl trisulphide, diacetyl, and 2,6-dimethylpyrazine were considered the most odour-potent. Copyright © 2003 John Wiley & Sons, Ltd.

  • Static headspace and Aroma Extract Dilution Analysis of Parmigiano Reggiano cheese
    Journal of Food Science, 2003
    Co-Authors: Michael C. Qian, Gary A. Reineccius
    Abstract:

    The aroma compounds in Parmigiano Reggiano cheese were studied with Aroma Extract Dilution Analysis (AEDA). Both static headspace and solvent extraction, high-vacuum distillation techniques were used to isolate aroma compounds. Thirty-six odor-active compounds had high flavor dilution values. Static headspace gas chromatography/olfactometry (GC/O) analysis found that acetaldehyde, 2-methylpropanal, 2-Methylbutanal, 3-methylbutanal, ethyl butanoaic, and ethyl hexanoate had low detection volumes, while high-vacuum distillation revealed that acetic, butanoic, hexanoic, octanoic, and decanoic acids, and ethyl butanoate, ethyl hexanoate, dimethyl trisulfide, methional, and phenylacetaldehyde had high flavor dilution values. In addition, some pyrazines appear to be important to the aroma of this cheese.

  • quantification of aroma compounds in parmigiano reggiano cheese by a dynamic headspace gas chromatography mass spectrometry technique and calculation of odor activity value
    Journal of Dairy Science, 2003
    Co-Authors: Michael C. Qian, Gary A. Reineccius
    Abstract:

    Potentially important aroma compounds in Parmigiano Reggiano cheese were quantified. Free fatty acids were isolated with ion-exchange chromatography and quantified by gas chromatography. Neutral aroma compounds were quantified with a purge-trap/gas chromatography-mass spectrometry with selective mass ion technique. Odor activity values were calculated based on sensory thresholds reported in literature. The calculated odor activity values suggest that 3-methylbutanal, 2-methylpropanal, 2-Methylbutanal, dimethyl trisulfide, diacetyl, methional, phenylacetaldehyde, ethyl butanoate, ethyl hexanoate, ethyl octanoate, acetic, butanoic, hexanoic, and octanoic acids are the most important aroma contributors to Parmigiano Reggiano cheese.

Jian Cai Zhu - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of the key aroma compounds in Laoshan green teas by application of odour activity value (OAV), gas chromatography-mass spectrometry-olfactometry (GC-MS-O) and comprehensive two-dimensional gas chromatography mass spectrometry (GC × G
    Food chemistry, 2020
    Co-Authors: Jian Cai Zhu, Yun Wei Niu, Zuo Bing Xiao
    Abstract:

    Abstract To investigate the key aroma compounds in Laoshan green teas (Huangshan (S1), Changling (S2), and Fangling (S3)), gas chromatography-mass spectrometry-olfactometry (GC-MS-O), a flame photometric detector (FPD), odor activity value (OAV), and comprehensive two-dimensional gas chromatography mass spectrometry (GC × GC-qMS) were employed. A total of 50 aroma compounds were perceived and 24 compounds were identified as important compounds related to OAV, such as dimethyl sulfide (OAV: 126–146), skatole (OAV: 27–50), furaneol (OAV: 8–27), (Z)-jasmone (OAV: 16–23), 2-Methylbutanal (OAV: 15–22), and 3-methylbutanal (OAV: 68–87). Furthermore, the S-curve method was used to research the effect of aroma compounds on the threshold of aroma recombination (AR). The AR thresholds decreased from 3.8 mL to 0.45, 0.66, 0.93, 0.95, 0.75, 1.09, 3.01, and 2.57 mL after addition of eight compounds (skatole, furaneol, (Z)-jasmone, α-damascenone, sclareololide, dihydroactinidiolide, vanillin, and δ-valerolactone), indicating that those compounds (OAV >1) were contributors to the overall aroma of Laoshan teas.

  • Comparison of Aroma-Active Volatiles in Oolong Tea Infusions Using GC-Olfactometry, GC-FPD, and GC-MS
    Journal of Agricultural and Food Chemistry, 2015
    Co-Authors: Jian Cai Zhu, Ling Ying Wang, Yun Wei Niu, He Xing Chen, Hong Lin Wang, Chang Shu, Dan Yu, Feng Chen, Zuo Bing Xiao
    Abstract:

    The aroma profile of oolong tea infusions (Dongdingwulong, DDWL; Tieguanyin, TGY; Dahongpao, DHP) were investigated in this study. Gas chromatography-olfactometry (GC-O) with the method of aroma intensity (AI) was employed to investigate the aroma-active compounds in tea infusions. The results presented forty-three, forty-five, and forty-eight aroma-active compounds in the TGY, DHP, and DDWL infusions, including six, seven, and five sulfur compounds, respectively. In addition, the concentration of volatile compounds in the tea infusions was further quantitated by solid phase microextraction-gas chromatography (SPME)-GC-MS and SPME-GC-flame photometric detection (FPD). Totally, seventy-six and thirteen volatile and sulfur compounds were detected in three types of tea infusions, respectively. Quantitative results showed that forty-seven aroma compounds were at concentrations higher than their corresponding odor thresholds. On the basis of the odor activity values (OAVs), 2-methylpropanal (OAV: 230-455), 3-methylbutanal (1-353), 2-Methylbutanal (34-68), nerolidol (108-184), (E)-2-heptenal (148-294), hexanal (134-230), octanal (28-131), β-damascenone (29-59), indole (96-138), 6-methyl-5-hepten-2-one (34-67), (R)-(-)-linalool (63-87), and dimethyl sulfide (7-1320) presented relatively higher OAVs than those of other compounds, indicating the importance of these compounds in the overall aroma of tea infusions.

  • Comparison of Aroma-Active Volatiles in Oolong Tea Infusions Using GC–Olfactometry, GC–FPD, and GC–MS
    2015
    Co-Authors: Jian Cai Zhu, Ling Ying Wang, Yun Wei Niu, He Xing Chen, Hong Lin Wang, Chang Shu, Feng Chen, Zuo Bing Xiao
    Abstract:

    The aroma profile of oolong tea infusions (Dongdingwulong, DDWL; Tieguanyin, TGY; Dahongpao, DHP) were investigated in this study. Gas chromatography–olfactometry (GC–O) with the method of aroma intensity (AI) was employed to investigate the aroma-active compounds in tea infusions. The results presented forty-three, forty-five, and forty-eight aroma-active compounds in the TGY, DHP, and DDWL infusions, including six, seven, and five sulfur compounds, respectively. In addition, the concentration of volatile compounds in the tea infusions was further quantitated by solid phase microextraction–gas chromatography (SPME)–GC–MS and SPME–GC–flame photometric detection (FPD). Totally, seventy-six and thirteen volatile and sulfur compounds were detected in three types of tea infusions, respectively. Quantitative results showed that forty-seven aroma compounds were at concentrations higher than their corresponding odor thresholds. On the basis of the odor activity values (OAVs), 2-methylpropanal (OAV: 230–455), 3-methylbutanal (1–353), 2-Methylbutanal (34–68), nerolidol (108–184), (E)-2-heptenal (148–294), hexanal (134–230), octanal (28–131), β-damascenone (29–59), indole (96–138), 6-methyl-5-hepten-2-one (34–67), (R)-(−)-linalool (63–87), and dimethyl sulfide (7–1320) presented relatively higher OAVs than those of other compounds, indicating the importance of these compounds in the overall aroma of tea infusions