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Nächste Überarbeitung 		Vorhergehende Überarbeitung
allium_cepa_l [2018/10/02 18:04]
andreas 		allium_cepa_l [2022/06/24 09:12] (aktuell)
andreas
Zeile 28: Zeile 28:
 "The most important compound found in the headspace of sliced onions by SPME-GC-MS after 1 min emission of volatiles was thiopropanal S-oxide. Also, some dipropenyl disulphides and propenyl propyl disulphides were identified. After 30 min, most of the thiopropanal-S-oxide disappeared, and other sulphur and non-sulphur compounds appeared in the GC chromatograms. The major constituents were diprop(en)yl disulphides. Similar constituents were also found in the water-slurred onions by headspace and direct SPME." \\ "The most important compound found in the headspace of sliced onions by SPME-GC-MS after 1 min emission of volatiles was thiopropanal S-oxide. Also, some dipropenyl disulphides and propenyl propyl disulphides were identified. After 30 min, most of the thiopropanal-S-oxide disappeared, and other sulphur and non-sulphur compounds appeared in the GC chromatograms. The major constituents were diprop(en)yl disulphides. Similar constituents were also found in the water-slurred onions by headspace and direct SPME." \\
 [Determination of fresh onion (Allium cepa L.) volatiles by solid phase microextraction combined with gas chromatography-mass spectrometry., Järvenpää, E.P., Zhang, Z., Huopalahti, R., King, J.W., Zeitschrift für Lebensmitteluntersuchung und-Forschung A, Vol.207(1), 1998, 39-43] [Determination of fresh onion (Allium cepa L.) volatiles by solid phase microextraction combined with gas chromatography-mass spectrometry., Järvenpää, E.P., Zhang, Z., Huopalahti, R., King, J.W., Zeitschrift für Lebensmitteluntersuchung und-Forschung A, Vol.207(1), 1998, 39-43]
 +
 +"[[http://www.thegoodscentscompany.com/data/rw1576741.html|3-Mercapto-2-methylpentan-1-ol]] was first detected in a complex thermally processed flavor and finally isolated from raw onions. The chemical structure of this new compound was identified by MS and (1)H NMR measurement and synthesis of the proposed structure. Sensory evaluation at different concentrations indicated that the flavor quality is strongly dependent on concentration. At low concentration (0.5 ppb) a pleasant meat broth, sweaty, onion, and leek-like odor can be perceived. On the basis of some isolation experiments and volatiles occurring in raw onions, a formation pathway is proposed. As one intermediate 3-mercapto-2-methylpentanal, another new strong flavor compound, was suggested. The presence of this compound in raw onions was confirmed by synthesis and comparison of MS and chromatographic data." \\
 +[Widder, Sabine, et al. "3-Mercapto-2-methylpentan-1-ol, a new powerful aroma compound." Journal of agricultural and food chemistry 48.2 (2000): 418-423]
  
 The lachrymatory factor thiopropanal-S-oxide is not released spontaneously as a by-product following the action of the enzyme alliinase, but is specifically synthesized from the intermediate sulphenic acid by a previously undiscovered enzyme, lachrymatory-factor synthase. \\ The lachrymatory factor thiopropanal-S-oxide is not released spontaneously as a by-product following the action of the enzyme alliinase, but is specifically synthesized from the intermediate sulphenic acid by a previously undiscovered enzyme, lachrymatory-factor synthase. \\
Zeile 37: Zeile 40:
 [Characterization of some Allium hybrids by aroma precursors, aroma profiles, and alliinase activity., Keusgen, M., Schulz, H., Glodek, J., Krest, I., Krüger, H., Herchert, N., Keller, J., Journal of agricultural and food chemistry, Vol.50(10), 2002, 2884-2890] [Characterization of some Allium hybrids by aroma precursors, aroma profiles, and alliinase activity., Keusgen, M., Schulz, H., Glodek, J., Krest, I., Krüger, H., Herchert, N., Keller, J., Journal of agricultural and food chemistry, Vol.50(10), 2002, 2884-2890]
  
-[[http://www.thegoodscentscompany.com/data/rw1576741.html|3-Mercapto-2-methylpentan-1-ol]] was identified as a potent onion odorant, especially in cooked onions.  It was also identified in other Allium species such as chives, scallions, and leek, whereas surprisingly garlic and bear's garlic did not contain this aroma compound. \\+[[http://www.thegoodscentscompany.com/data/rw1576741.html|3-Mercapto-2-methylpentan-1-ol]] was identified as a potent onion odorant, especially in cooked onions.  It was also identified in other Allium species such as chives, scallions, and leek, whereas surprisingly garlic and bears garlic did not contain this aroma compound. \\
 [Quantitation of the intense aroma compound 3-mercapto-2-methylpentan-1-ol in raw and processed onions (Allium cepa) of different origins and in other Allium varieties using a stable isotope dilution assay., Granvogl, M., Christlbauer, M., Schieberle, P., Journal of agricultural and food chemistry, Vol.52(10), 2004, 2797-2802] [Quantitation of the intense aroma compound 3-mercapto-2-methylpentan-1-ol in raw and processed onions (Allium cepa) of different origins and in other Allium varieties using a stable isotope dilution assay., Granvogl, M., Christlbauer, M., Schieberle, P., Journal of agricultural and food chemistry, Vol.52(10), 2004, 2797-2802]
  
Zeile 55: Zeile 58:
  
 "Most odorants typically activate combinations of odorant receptors, which may be narrowly or broadly tuned. Consequently, a specific receptor activation pattern will define an odor quality. In contrast, here we show that just 1 of the 391 human odorant receptors, OR2M3, responded exclusively to 3-mercapto-2-methylpentan-1-ol of the 190 key food odorants tested, with a half maximal effective concentration at submicromolar concentration. Moreover, neither the Denisovan OR2M3 nor the closest OR2M3 homologs from five species did respond to this compound. This outstanding specificity of extremely narrowly tuned human OR2M3 can explain both odor qualities and odor threshold trend within a homologous series of 3-mercapto-2-methylalkan-1-ols and suggests a modern human-specific, food-related function of OR2M3 in detecting a single onion key food odorant." \\ "Most odorants typically activate combinations of odorant receptors, which may be narrowly or broadly tuned. Consequently, a specific receptor activation pattern will define an odor quality. In contrast, here we show that just 1 of the 391 human odorant receptors, OR2M3, responded exclusively to 3-mercapto-2-methylpentan-1-ol of the 190 key food odorants tested, with a half maximal effective concentration at submicromolar concentration. Moreover, neither the Denisovan OR2M3 nor the closest OR2M3 homologs from five species did respond to this compound. This outstanding specificity of extremely narrowly tuned human OR2M3 can explain both odor qualities and odor threshold trend within a homologous series of 3-mercapto-2-methylalkan-1-ols and suggests a modern human-specific, food-related function of OR2M3 in detecting a single onion key food odorant." \\
 +3-Mercapto-2-methylpentan-1-ol (0.0014 ng/L) and 3-mercapto-2-methylhexan-1-ol (0.0080 ng/L) showed extremely low thresholds. \\
 [Noe, F., Polster, J., Geithe, C., Kotthoff, M., Schieberle, P., & Krautwurst, D. (2016). OR2M3: A Highly Specific and Narrowly Tuned Human Odorant Receptor for the Sensitive Detection of Onion Key Food Odorant 3-Mercapto-2-methylpentan-1-ol. Chemical Senses, bjw118.] [Noe, F., Polster, J., Geithe, C., Kotthoff, M., Schieberle, P., & Krautwurst, D. (2016). OR2M3: A Highly Specific and Narrowly Tuned Human Odorant Receptor for the Sensitive Detection of Onion Key Food Odorant 3-Mercapto-2-methylpentan-1-ol. Chemical Senses, bjw118.]
  
allium_cepa_l.1538496289.txt.gz · Zuletzt geändert: 2018/10/02 18:04 von andreas

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