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coffea_arabica_l [2017/09/27 11:58]
andreas
coffea_arabica_l [2022/02/06 15:03] (aktuell)
andreas
Zeile 5: Zeile 5:
 "Coffea arabica is believed to be the first species of coffee to be cultivated, being grown in southwest Ethiopia for well over 1,000 years." [[http://en.wikipedia.org/wiki/Coffea_arabica]] "Coffea arabica is believed to be the first species of coffee to be cultivated, being grown in southwest Ethiopia for well over 1,000 years." [[http://en.wikipedia.org/wiki/Coffea_arabica]]
  
-"The volatile components of roasted Arabica and Robusta coffees (powder and brew) were analysed by gas chromatography-olfactometry (GC/Owhich revealed the odorants having the highest odor-activity values (ratio of concentration to odor threshold). This procedure resulted in 38 odorants of which 32 were identified. The powders of the two coffee varieties differed in the concentration levels of these compoundsThe results indicate that the flavor difference between Arabica and Robusta coffee (powder and brew) are mainly due to the predominance of enoloxo compounds (sotolonabhexonfuraneol3,4-dimethyl-2-hydroxy-2-cyclopentenonein the former and of 3,5-dimethyl-2-ethylpyrazine, 2,3-diethyl-5-methylpyrazine, 4-ethylguaiacol and 4-vinylguaiacol in the latter. Preparation of brews enhanced the flavor difference, as the concentration levels of water-soluble odorants (furaneolsotolon, abhexonresponsible for the “sweet-caramel” flavour note increased more in the Arabica than in the Robusta coffee. On the other handthe alkylpyrazines and guaiacols were responsible for the “spicy, harsh-earthy” aroma of the Robusta coffee. Quantification of selected odorants using a stable isotope dilution assay confirmed the differences between the Arabica and Robusta coffees (brew) found by GC/O." \\+Most potant odorants (highest FD-factor) of roasted Colombian coffee powder were: 2-methyl-3-furan-thiol (meaty), 2-furanmethanthiol (rosty, coffee-like), methional (cooked potatoes), 3-mercapto-3-methylbutylformate (catty, sweaty), 2-isobutyl-3-methoxypyrazine (paprika-like), 2/3-methylbutyric acid, (E)-ß-damascenone, and furaneol. In coffee beverages the "peasy" off-note is perceivable beginning at 300µg/l and higher. Non-peasy coffees contain this alkoxy pyrazine only in ranges less than 100µg/kg. Some typical mouldy tasting coffees contained about 1µg/kg of 2,4,6-trichloranisole (odor threshold about 0.05ng/l). The earthy note of Robusta coffee corresponds to a great extent to 2-methylisoborneol (2-MIB). This musty, earthy smelling compound with a very low odour threshold of 2.5ng/l in water (2.5ppt) is found in Robusta coffees in amounts to about 200ng/kg, whereas in Arabica coffees it was found at max. 50ng/kg, which is too low for recognition in coffee beverages. \\ 
 +[Vitzthum, O. G., Becker, R., Hölscher, W., and Weisemann, C. "Aroma impact compounds in coffee." in: Aroma production and application. Proceedings of the 3rd Wartburg Aroma Symposium 1991. Editors M. RotheH.-P. KruseDeutsches Institut für Ernährungsforschung Potsdam-Rehbrücke (1992)211-223] 
 + 
 +Most important odorants of roasted Arabica coffee powder were (highest FD-factor 2048) identified as 3-mercapto-3-methylbutylformate (catty)3,5-dimethyl-2-ethylpyrazine (earthy-roasty) and (E)-ß-damascenone (honey-like). 2-methyl-3-furan-thiol (meaty), 2,3-diethyl-5-methylpyrazine (earthy-roasty) and bis(2-methyl-3-furyl)disulphide (meatysweetshowed very low threshold values (0.001-0.01 ng/1 air). 3,5-Dimethyl-2-ethylpyrazine appeared with the highest FD-factor in Arabica and Robusta coffee powders\\ 
 +"2,3-Diethyl-5-methylpyrazine and 4-ethylguaiacol were predominant in the Robusta coffee and 3-mercapto-3-methylbutylformate, sotolon and abhexon in the Arabica coffee. Further significant differences were found for 2-methyl-3-furanthiol, phenylacetaldehyde, 3,4-dimethyl-2-cyclopentenol-1-one, 2-/3-methylbutanoic acid and linalool, all predominating in the Arabica coffee, and for 3-methyl-2-buten-1-thiol, which prevailed in the Robusta coffee." \\
 [Aroma impact compounds of arabica and robusta coffee. Qualitative and quantitative investigations. Blank, I., Sen, A.,Grosch, W., In Quatorzieme colloque scientifique international sur le cafe, San Francisco, 14-19 juillet 1991, 117-129)]  [Aroma impact compounds of arabica and robusta coffee. Qualitative and quantitative investigations. Blank, I., Sen, A.,Grosch, W., In Quatorzieme colloque scientifique international sur le cafe, San Francisco, 14-19 juillet 1991, 117-129)] 
  
-|{{:sotolon.jpg|sotolon}} \\ sotolon \\ (3-hydroxy-4,5-dimethyl-2(5H)-furanone, caramel furanone) |{{:hdmf.jpg|furaneol}} \\ furaneol \\ (4-hydroxy-2,5-dimethyl-3(2H)-furanone) |{{:2-ethyl-3_5-dimethylpyrazine.jpg|2-ethyl-3,5-dimethylpyrazine}} \\ 2-ethyl-3,5-dimethylpyrazine |{{4-vinylguaiacol.jpg|4-vinylguaiacol}} \\ 4-vinylguaiacol |{{:furfurylmercaptan.jpg| 2-furfurylthiol }}  furfuryl mercaptan (2-furfurylthiol) |+|{{:sotolon.jpg|sotolon}} \\ sotolon \\ (3-hydroxy-4,5-dimethyl-2(5H)-furanone) |{{:hdmf.jpg|furaneol}} \\ furaneol \\ (4-hydroxy-2,5-dimethyl-3(2H)-furanone) |{{:2-ethyl-3_5-dimethylpyrazine.jpg|2-ethyl-3,5-dimethylpyrazine}} \\ 2-ethyl-3,5-dimethylpyrazine |{{4-vinylguaiacol.jpg|4-vinylguaiacol}} \\ 4-vinylguaiacol |{{:furfurylmercaptan.jpg| 2-furfurylthiol }} \\ furfuryl mercaptan \\ (2-furfurylthiol) |
  
 "The potent odorants were quantified in a sample of roasted Arabica coffee. On the basis of the results, 27 odorants were dissolved in an oil/water mixture. The flavor profile of the model obtained was very close to that of the real sample. In duo and triangle tests, the model was compared with models missing one or more odorants. These experiments indicated that 2-furfurylthiol, 4-vinylguaiacol, several alkyl pyrazines, furanones, acetaldehyde, propanal, methylpropanal, and 2- and 3-methylbutanal had the greatest impact on the coffee flavor." The omission experiments for [[http://www.thegoodscentscompany.com/data/rw1008451.html|2-furfurylthiol]] confirmed that it is a key component of coffee "The potent odorants were quantified in a sample of roasted Arabica coffee. On the basis of the results, 27 odorants were dissolved in an oil/water mixture. The flavor profile of the model obtained was very close to that of the real sample. In duo and triangle tests, the model was compared with models missing one or more odorants. These experiments indicated that 2-furfurylthiol, 4-vinylguaiacol, several alkyl pyrazines, furanones, acetaldehyde, propanal, methylpropanal, and 2- and 3-methylbutanal had the greatest impact on the coffee flavor." The omission experiments for [[http://www.thegoodscentscompany.com/data/rw1008451.html|2-furfurylthiol]] confirmed that it is a key component of coffee
Zeile 17: Zeile 21:
 [Steinhart H, Holscher W. In Proceedings of the 14th ASIC Meeting, San Francisco, 1991, 156-164] \\ [Steinhart H, Holscher W. In Proceedings of the 14th ASIC Meeting, San Francisco, 1991, 156-164] \\
 [Coffee flavour: an overview., Buffo, R.A., Cardelli-Freire, C., Flavour and fragrance journal, 19(2), 2004, 99-104] [[http://www2.hcmuaf.edu.vn/data/lhquang/file/Coffee/coffee%20flavour.pdf]] [Coffee flavour: an overview., Buffo, R.A., Cardelli-Freire, C., Flavour and fragrance journal, 19(2), 2004, 99-104] [[http://www2.hcmuaf.edu.vn/data/lhquang/file/Coffee/coffee%20flavour.pdf]]
 +
 +| {{:methional.jpg|methional}} \\ methional \\ //(potato-like)// | {{3mercapto3methylbutylformate.png| 3-mercapto-3-methylbutyl formate }} \\ 3-mercapto-3-methylbutyl formate \\ //(catty roasty)// |
  
 "The more potent odorants in a sample of medium-roasted Arabica coffee and in the corresponding brew were quantified. Large amounts ( >75%) of acetaldehyde, 2,3-butanedione, 2,3-pentanedione, vanillin and some furanones were extracted from the coffee brew, whereas the yields of the more unpolar compounds, such as 3-isobutyl-2-methoxypyrazine, (E)-β-damascenone and the unstable 2-furfurylthiol were low (<25%). On the basis of quantitative data an aroma model was prepared for the brew. In triangle tests, models containing the complete set of 24 odorants were compared with a model missing one or more odorants. These experiments indicated that the aroma of the brew was mainly caused by some alkylpyrazines, furanones and phenols, and by 2-furfurylthiol, methional and 3-mercapto-3-methylbutyl formate. The higher impact of both methional and the formate on the aroma of the brew and the lower aroma activity of 4-vinylguaiacol were in contrast to results obtained in a previous study for ground coffee of the same provenance and roast degree." \\ "The more potent odorants in a sample of medium-roasted Arabica coffee and in the corresponding brew were quantified. Large amounts ( >75%) of acetaldehyde, 2,3-butanedione, 2,3-pentanedione, vanillin and some furanones were extracted from the coffee brew, whereas the yields of the more unpolar compounds, such as 3-isobutyl-2-methoxypyrazine, (E)-β-damascenone and the unstable 2-furfurylthiol were low (<25%). On the basis of quantitative data an aroma model was prepared for the brew. In triangle tests, models containing the complete set of 24 odorants were compared with a model missing one or more odorants. These experiments indicated that the aroma of the brew was mainly caused by some alkylpyrazines, furanones and phenols, and by 2-furfurylthiol, methional and 3-mercapto-3-methylbutyl formate. The higher impact of both methional and the formate on the aroma of the brew and the lower aroma activity of 4-vinylguaiacol were in contrast to results obtained in a previous study for ground coffee of the same provenance and roast degree." \\
Zeile 42: Zeile 48:
 [Chlorogenic acid reduces the plasma glucose peak in the oral glucose tolerance test: effects on hepatic glucose release and glycaemia., Bassoli, B.K., Cassolla, P., Borba‐Murad, G.R., Constantin, J., Salgueiro‐Pagadigorria, C.L., Bazotte, R.B., de Souza, H.M., Cell biochemistry and function, 26(3), 2008, 320-328] [Chlorogenic acid reduces the plasma glucose peak in the oral glucose tolerance test: effects on hepatic glucose release and glycaemia., Bassoli, B.K., Cassolla, P., Borba‐Murad, G.R., Constantin, J., Salgueiro‐Pagadigorria, C.L., Bazotte, R.B., de Souza, H.M., Cell biochemistry and function, 26(3), 2008, 320-328]
  
-{{:coffea_arabica.jpg?500}} \\+{{:coffea_arabica.jpg}} \\
 Köhler,F.E., Medizinal Pflanzen, vol.2 t.106 (1890) \\ Köhler,F.E., Medizinal Pflanzen, vol.2 t.106 (1890) \\
 [[http://plantgenera.org/species.php?id_species=262279]] [[http://plantgenera.org/species.php?id_species=262279]]
coffea_arabica_l.1506506283.txt.gz · Zuletzt geändert: 2017/09/27 11:58 von andreas