Deutsche Forschungsanstalt fur Lebensmittelchemie

Freising, Germany

Deutsche Forschungsanstalt fur Lebensmittelchemie

Freising, Germany
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Langos D.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Granvogl M.,TU Munich | Schieberle P.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Schieberle P.,TU Munich
Journal of Agricultural and Food Chemistry | Year: 2013

Application of aroma extract dilution analysis (AEDA) on the volatiles isolated from a commercial Bavarian wheat beer (WB A) eliciting its typical aroma profile, best described by a clove-like, phenolic odor quality, revealed 36 odorants in the flavor dilution (FD) factor range from 16 to 4096. Among them, 2-methoxy-4-vinylphenol (clove-like) and 2-phenylethanol (flowery) showed the highest FD factors. AEDA of a second wheat beer (WB B), somewhat lacking the typical wheat beer odor note, revealed 32 odor-active components in the FD factor range from 32 to 8192. Among them, 2-phenylethanol, (E)-β- damascenone (cooked apple-like) and 3-methylbutanol (malty) were detected with the highest FD factors. Next, all odorants evaluated with an FD factor ≥32 were quantitated by stable isotope dilution assays in both beers, and the odor activity values (OAVs; ratio of concentration to odor threshold) were calculated. Thereby, ethanol, (E)-β-damascenone, 3-methylbutyl acetate, ethyl methylpropanoate, and ethyl butanoate showed the highest OAVs in WB A, followed by acetaldehyde, 3-methylbutanol, and dimethyl sulfide. In WB B, ethanol, (E)-β-damascenone, ethyl methylpropanoate, ethyl butanoate, and 3-methylbutyl acetate showed the highest OAVs. Whereas most aroma compounds were present in the same order of magnitude in both beer samples, in particular, 2-methoxy-4-vinylphenol and 4-vinylphenol (smoky, leather-like) were by factors of 13 and 15, respectively, higher in WB A. For the first time, the overall aroma of wheat beer (WB A) was successfully simulated on the basis of 27 reference compounds in their natural concentrations using water/ethanol (95:5; v/v) as the matrix. © 2013 American Chemical Society.


Grosshauser S.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Schieberle P.,Deutsche Forschungsanstalt fur Lebensmittelchemie
Journal of Agricultural and Food Chemistry | Year: 2013

Application of aroma extract dilution analysis (AEDA) on the volatile fraction isolated from pan-fried white mushrooms (Agaricus bisporus L.) revealed 40 odor-active compounds in the flavor dilution (FD) factor range of 8-8192, among which the caramel-like smelling 4-hydroxy-2,5-dimethylfuran-3(2H)-one showed the highest FD factor of 8192, followed by 2-propionyl-1-pyrroline (popcorn-like) and 3-hydroxy-4,5-dimethylfuran-2(5H)-one (seasoning-like). A total of 36 compounds are reported for the first time in processed mushrooms, and 25 odorants showing the highest FD factors were then quantitated by stable isotope dilution assays and their odor activity values (OAVs) were calculated as ratio of their concentrations to their odor thresholds. Among them, 3-methylbutanal (malty), 3-(methylthio)propanal (cooked potato), and 2-acetyl-1-pyrroline (popcorn-like) showed the highest OAVs (>100) in the pan-fried mushrooms, followed by 1-octen-3-one, 2-propionyl-1-pyrroline, 4-hydroxy-2,5-dimethylfuran-3(2H)-one, phenylacetaldehyde, 2,3-diethyl-5- methylpyrazine, and 3-hydroxy-4,5-dimethylfuran-2(5H)-one with OAVs >10. An aqueous aroma recombinate containing 13 odorants (OAV > 1) in their actual concentrations in the fried mushrooms showed a good similarity to the original aroma profile. The quantitation of the key odorants in raw mushrooms, identified with high FD factors during the AEDA, revealed that numerous odorants were quantitatively changed by the frying process, but in particular the concentrations of 2-phenylacetaldehyde and 3-methylbutanal were higher by factors of ∼40 and 6, respectively, compared to the amounts in the processed mushrooms. The data suggested an enzymatic formation of both Strecker aldehydes by the cut mushroom tissue. In total, 26 odorants were newly identified in raw mushrooms. © 2013 American Chemical Society.


Granvogl M.,TU Munich | Beksan E.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Schieberle P.,TU Munich
Journal of Agricultural and Food Chemistry | Year: 2012

2-Substituted-5-methyl-3-oxazolines, a novel class of aroma precursors that are able to release the respective Strecker aldehydes by hydrolysis, were identified. Hydrolysis can take place after the addition of water or with human saliva during mastication, respectively. 2-Isobutyl-, 2-sec-isobutyl-, 2-isopropyl, and 2-benzyl-5-methyl-3-oxazolines were synthesized and structurally identified by means of gas chromatography-mass spectrometry (GC-MS) in the electron impact mode and in the chemical ionization mode as well as by one- and two-dimensional NMR experiments. With these compounds at hand, a variety of stability experiments were performed using headspace-GC-MS or proton transfer reaction-MS techniques on the basis of stable isotope dilution assays, proving the ability to release the respective Strecker aldehydes was dependent on the pH value as well as on the hydrolysis time. After the addition of water at 37 °C, for example, >70 mol % of 3-methylbutanal or >40 mol % of phenylacetaldehyde was liberated from a solution of 2-isobutyl-5-methyl-3- oxazoline or 2-benzyl-5-methyl-3-oxazoline, respectively, after 5 min. Furthermore, the presence of 2-isobutyl-5-methyl-3-oxazoline in dark chocolate containing 70% cocoa was proven by GC-MS. © 2012 American Chemical Society.


Hammer M.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Schieberle P.,Deutsche Forschungsanstalt fur Lebensmittelchemie
Journal of Agricultural and Food Chemistry | Year: 2013

Due to the high number of double bonds, ω-3-polyunsaturated fatty acids such as eicosapentaenoic aid (EPA) or docosahexaenoic acid (DHA) are prone to rapid oxidation, leading to the formation of intense taints often described as "fishy". To clarify the compounds responsible for such off-flavors, EPA, DHA, and α-linolenic acid (ALA) were oxidized singly either in the presence of copper ions or in the presence of lipoxygenase. The autoxidation of EPA and DHA led to a mixture of odorants eliciting an overall fishy odor quality, whereas neither the oxidation of ALA by copper ions nor that by lipoxygenase led to an unpleasant odor. Application of aroma extract dilution analysis (AEDA) on the volatiles generated by autoxidation of EPA revealed trans-4,5-epoxy-(E,Z)-2,7-decadienal, identified for the first time as fatty acid degradation product, (Z)-1,5-octadien-3-one, (Z)-3-hexenal, (Z,Z)-2,5-octadienal, (Z,Z)-3,6-nonadienal, and (E,E,Z)-2,4,6-nonatrienal with the highest flavor dilution (FD) factors. The autoxidation as well as the enzymatic oxidation of all three acids led to the same odorants, but with different FD factors depending on the acid and/or the type of oxidation applied. Thus, the results suggested that a defined ratio of a few odorants is needed to generate a fishy off-flavor. © 2013 American Chemical Society.


Burdack-Freitag A.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Schieberle P.,Deutsche Forschungsanstalt fur Lebensmittelchemie
Journal of Agricultural and Food Chemistry | Year: 2010

Application of a comparative aroma extract dilution analysis on aroma distillates isolated from either raw Italian hazelnuts or a roasted hazelnut material produced thereof revealed 37 odor-active compounds in the raw nuts, whereas 46 aroma compounds were detected in the roasted nut material. 2-Methoxy-3-isopropylpyrazine and 2-methoxy-3,5-dimethylpyrazine as well as 5-methyl-4-heptanone predominated with the highest flavor dilution factors in the raw nuts, whereas 2-acetyl-1-pyrroline, 2-propionyl-1-pyrroline, 2-furfurylthiol, and 2-thenylthiol as well as (Z)-2-octenal, (Z)-2-nonenal, and (Z)-2-decenal showed the highest odor activities in the roasted nuts. These odorants, as well as several others, were previously unknown in hazelnuts. In addition, the intensely seasoning-like smelling 3,5,5′-trimethyl-2(5H)- furanone was identified for the first time as a food aroma compound on the basis of a newly developed synthetic route and NMR measurements. © 2010 American Chemical Society.


Seideneck R.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Schieberle P.,Deutsche Forschungsanstalt fur Lebensmittelchemie
European Food Research and Technology | Year: 2011

Application of a comparative aroma extract dilution analysis on a hand-squeezed (juice A) and an industrially squeezed, unpasteurised orange juice (juice B), revealed qualitatively almost the same set of odour-active compounds. However, while in juice A, vanillin, ethyl butanoate, wine lactone, (Z)-3-hexenal, (S)-ethyl 2-methylbutanoate and (S)-linalool were detected with the highest flavour dilution (FD) factors, in juice B prepared by means of an FMC extractor, several compounds, like (R)-limonene, (R)-α-pinene and octanal showed higher FD factors, in addition to ethyl butanoate, wine lactone and (S)-ethyl 2-methylbutanoate. Quantification of seventeen odorants in both juices by means of stable isotope dilution assays followed by a calculation of odour activity values (OAV; ratio of concentration to odour threshold) revealed a clear change in the ranking order: while (S)-ethyl 2-methylbutanoate, (R)-limonene, (Z)-3-hexenal and linalool were first in rank among the odorants of juice A, in juice B, (R)-limonene and (S)-linalool followed by (S)-ethyl 2-methylbutanoate showed the highest OAVs. Sensory experiments revealed that the much higher concentrations of the seven peel oil constituents, and the lack in (Z)-3-hexenal, are the reason for the aroma differences observed for both juices. Further experiments indicated that lowering the pressure during commercial juicing, and also the avoidance of a freezing/thawing process could be helpful in getting closer to the aroma of hand-squeezed orange juice, because peel oil constituents are lowered and, in particular, the latter procedure leads to a complete degradation of (Z)-3-hexenal. © 2011 Springer-Verlag.


Chetschik I.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Granvogl M.,TU Munich | Schieberle P.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Schieberle P.,TU Munich
Journal of Agricultural and Food Chemistry | Year: 2010

By means of stable isotope dilution assays (SIDA), 26 odor-active compounds, previously characterized by GC-olfactometry (GC-O), were quantitated in raw peanuts, and the concentrations of 38 odorants were determined in pan-roasted peanut meal. On the basis of the quantitative data and odor thresholds determined in vegetable oil, the odor activity values (OAVs) of the most important aroma compounds in raw as well as in pan-roasted peanut meal were calculated. 3-Isopropyl-2-methoxypyrazine, acetic acid, and 3-(methylthio)propanal showed the highest OAVs in raw peanuts, ws methanethiol, 2,3-pentanedione, 3-(methylthio)propanal, and 2- and 3-methylbutanal as well as the intensely popcorn-like smelling 2-acetyl-1-pyrroline revealed the highest OAV in the pan-roasted peanut meal. Aroma recombination studies confirmed the importance, in particular, of methanethiol and of lipid degradation products in the characteristic aroma of the freshly roasted peanut material. To evaluate additive effects on the overall aroma, the concentrations of eight pyrazines, previously not detected by GC-O among the odor-active volatiles, were additionally quantitated in the panroasted peanut meal. A sensory experiment in which the eight pyrazines were added to the recombinate clearly revealed that these volatiles did not show an impact on the overall aroma. Finally, selected odorants were quantitated in commercial peanut products to confirm their important role in peanut aroma. © 2010 American Chemical Society.


Frank S.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Wollmann N.,TU Munich | Schieberle P.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Hofmann T.,TU Munich
Journal of Agricultural and Food Chemistry | Year: 2011

By application of aroma extract dilution analysis (AEDA) on the volatile fraction isolated from a Dornfelder red wine, 31 odor-active compounds were identified by means of HRGC-MS and comparison with reference compounds. A total of 27 odorants, judged with high FD factors by means of AEDA, was quantitated by means of stable isotope dilution assays, and acetaldehyde was determined enzymatically. In addition, 36 taste-active compounds were analyzed by means of HPLC-UV, HPLC-MS/MS, and ion chromatography. The quantitative data obtained for the identified aroma and taste compounds enabled for the first time the reconstruction of the overall flavor of the red wine. Sensory evaluation of both the aroma and taste profiles of the authentic red wine and the recombinate revealed that Dornfelder red wine was closely mimicked. Moreover, it was demonstrated that the high molecular weight fraction of red wine is essential for its astringent taste impression. By comparison of the overall odor of the aroma recombinate in ethanol with that of the total flavor recombinate containing all tastants, it was shown for the first time that the nonvolatile tastants had a strong influence on the intensity of certain aroma qualities. © 2011 American Chemical Society.


Harteneck C.,University of Tübingen | Klose C.,University of Tübingen | Krautwurst D.,Deutsche Forschungsanstalt fur Lebensmittelchemie
Advances in Experimental Medicine and Biology | Year: 2011

In humans, 27 TRP channels from 6 related families contribute to a broad spectrum of cellular functions, such as thermo-, pressure-, volume-, pain- and chemosensation. Pain and inflammation-inducing compounds represent potent plant and animal defense mechanisms explaining the great variety of the naturally occurring, TRPV1-, TRPM8-, and TRPA1-activating ligands. The discovery of the first vanilloid receptor (TRPV1) and its involvement in nociception triggered the euphoria and the hope in novel therapeutic strategies treating pain, and this clear-cut indication inspired the development of TRPV1-selective ligands. On the other hand the nescience in the physiological role and putative clinical indication hampered the development of a selective drug in the case of the other TRP channels. Therefore, currently only a handful of mostly un-selective blocker is available to target TRP channels. Nevertheless, there is an ongoing quest for new, natural or synthetic ligands and modulators. In this chapter, we will give an overview on available broad-range blocker, as well as first TRP channel-selective compounds. © 2011 Springer Science+Business Media B.V.


Burdack-Freitag A.,Deutsche Forschungsanstalt fur Lebensmittelchemie | Schieberle P.,Deutsche Forschungsanstalt fur Lebensmittelchemie
Journal of Agricultural and Food Chemistry | Year: 2012

The concentrations of 19 odorants, recently characterized by GC-olfactometry and aroma extract dilution analysis as the most odor-active compounds in raw hazelnuts, were quantitated by stable isotope dilution assays (SIDA). Calculation of odor activity values (OAV) on the basis of odor thresholds in oil revealed high OAVs, in particular for linalool, 5-methyl-4-heptanone, 2-methoxy-3,5-dimethylpyrazine, and 4-methylphenol. A model mixture in sunflower oil containing the 13 odorants showing OAVs above 1 in their natural concentrations resulted in a good similarity compared to the overall nut-like, fruity aroma of the raw hazelnuts. Quantitation of the 25 most odor-active compounds in roasted hazelnut paste by SIDA showed clear changes in the concentrations of most odorants, and formation of new odor-active compounds induced by the roasting process was observed. The highest OAVs were calculated for 3-methylbutanal (malty), 2,3-pentanedione (buttery), 2-acetyl-1-pyrroline (popcorn), and (Z)-2-nonenal (fatty), followed by dimethyl trisulfide, 2-furfurylthiol, 2,3-butanedione, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone. The aroma of a model mixture containing the 19 odorants with OAVs above 1 in their actual concentrations in the roasted nut material was judged to elicit a very good similarity to the popcorn-like, coffee-like, and sweet-smoky aroma of the roasted hazelnut paste. New SIDAs were developed for the quantitation of 5-methyl-4-heptanone, 5-methyl-(E)-2-hepten-4-one, 2-thenylthiol, and 3,5,5-trimethyl-2(5H)-furanone. © 2012 American Chemical Society.

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