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--- pyrus_communis_l [2019/02/03 16:09]
andreas
+++ pyrus_communis_l [2022/01/23 17:59] (aktuell)
andreas
@@ Zeile 9: / Zeile 9: @@
 [[http://en.wikipedia.org/wiki/European_Pear]]
-"Eight pear varieties including ‘Bartlett’, ‘Packham's Triumph’, ‘Anjou’, ‘Comice’, ‘Bosc’, ‘Seckel’, ‘Vicar of Winkfield’ and ‘Forelle’ were ripened optimally and volatile compounds from dynamic headspace were collected and identified by GC/MS. Among 112 compounds identified from all varieties, 47 compounds are reported the first time in pears. The volatile profiles of these eight varieties are characterized by compounds in groups of esters, alcohols, hydrocarbons, aldehydes, and ketones. Esters of short to medium chain alcohols and their corresponding acids with or without some degree of unsaturation are always present as a major group of compounds in all varieties. Esters comprise 60 to 98% of total volatiles among the varieties. Hexyl acetate represents the major ester in all cultivars except ‘Bosc’ and ‘Vicar of Winkfield’ which produced butyl acetate as a major ester, and ‘Seckel’ produced ethyl 2,4 decadienoate as the major ester. Decadienoate esters were detected in all varieties, but varied in amount and isomerization characteristics. Straight-chain alcohols with 2 to 8 carbons are present as the second largest group in the profile. Two isomeric forms (E,E and E,Z) of the sesquiterpene hydrocarbon, α-farnesene, are always present in the profiles but vary considerably in amount. A small number of aldehydes and ketones are also found in some varieties but present in very small amounts.\\
+The compounds identified in the volatile essence of fresh, ripe Bartlett pears included alcohols C2-C8 and their corresponding acetates as well as methyl and ethyl esters of n-octanoic, 3-hydroxyoctanoic, (E)-2-octenoic, decanoic, (Z)-4-decenoic, (E)-2-decenoic, (E,Z)-2,4-decadienoic, and (E,E)-2,4-decadienoic acids. \\
+[Heinz, D. E., and W. G. Jennings. "Volatile components of Bartlett pear. V." Journal of Food Science 31.1 (1966): 69-80]
+"Eight pear varieties including ‘Bartlett’, ‘Packham's Triumph’, ‘Anjou’, ‘Comice’, ‘Bosc’, ‘Seckel’, ‘Vicar of Winkfield’ and ‘Forelle’ were ripened optimally and volatile compounds from dynamic headspace were collected and identified by GC/MS. Among 112 compounds identified from all varieties, 47 compounds are reported the first time in pears. The volatile profiles of these eight varieties are characterized by compounds in groups of esters, alcohols, hydrocarbons, aldehydes, and ketones. Esters of short to medium chain alcohols and their corresponding acids with or without some degree of unsaturation are always present as a major group of compounds in all varieties. Esters comprise 60 to 98% of total volatiles among the varieties. Hexyl acetate represents the major ester in all cultivars except ‘Bosc’ and ‘Vicar of Winkfield’ which produced butyl acetate as a major ester, and ‘Seckel’ produced ethyl 2,4-decadienoate as the major ester. Decadienoate esters were detected in all varieties, but varied in amount and isomerization characteristics. Straight-chain alcohols with 2 to 8 carbons are present as the second largest group in the profile. Two isomeric forms (E,E and E,Z) of the sesquiterpene hydrocarbon, α-farnesene, are always present in the profiles but vary considerably in amount. A small number of aldehydes and ketones are also found in some varieties but present in very small amounts.\\
 |{{:farnesene_eealpha.jpg|(E,E)-α-farnesene}} \\ (E,E)-α-farnesene \\ //(woody green)// |{{:ethyl24decadienoatezz.jpg|ethyl-(2Z,4Z)-decadienoate}} \\ ethyl-(2Z,4Z)-decadienoate \\ //(pear fruity)// |{{:ethyl24decadienoateez.jpg|ethyl-(2E,4Z)-decadienoate}} \\ ethyl-(2E,4Z)-decadienoate \\ //(pear green)// |{{:ethyl24decadienoateee.jpg|ethyl-(2E,4E)-decadienoate}} \\ ethyl-(2E,4E)-decadienoate \\ //(fermented)// |
@@ Zeile 29: / Zeile 32: @@
 Important aroma components (high Flavor Dilution (FD) factors) were e.g. (E)-β-damascenone, ethyl (S)-2-methylbutanoate, and 2-phenylethanol. \\
 [Willner, Bianca, Michael Granvogl, and Peter Schieberle. "Characterization of the key aroma compounds in Bartlett pear brandies by means of the sensomics concept." Journal of agricultural and food chemistry 61.40 (2013): 9583-9593]
+"While ethyl (E,Z)-2,4-decadienoate (pear-like, metallic odor impression), hexyl acetate (green, fruity), and acetic acid (vinegar-like) showed the highest concentrations in Bartlett pears, ethanol (ethanolic), acetic acid, 3-methyl-1-butanol (malty), 1-hexanol (grassy, marzipan-like), (S)-2- and 3-methylbutanoic acid (sweaty), and 2-phenylethanol (flowery, honey-like) were present at the highest amounts in the fermented mash. The key aroma compounds were quantitated in each pear brandy production step (pears, fermented mash, distillate, and aged distillate) by stable isotope dilution analysis showing a clear influence of each step on the overall aroma of the spirit and, consequently, revealing clearly changing concentrations (e.g., of ethyl (S)-2-methylbutanoate, (E)-β-damascenone, ethyl (E,Z)-2,4-decadienoate, and ethyl (E,E)-2,4-decadienoate) and different aroma perceptions during the manufacturing process. In addition, the concentrations of the so-called “pear esters” ethyl (E,Z)-2,4-decadienoate and ethyl (E,E)-2,4-decadienoate were determined in 6 different pear varieties (Abate Fetel, Anjou, Bartlett, Forelle, Kaiser Alexander, and Packham's Triumph) clearly demonstrating the aroma potential of the variety Bartlett, which is mostly used for brandy production due to the high amounts of both esters eliciting a typical pear-like odor impression." \\
+[Zierer, Bianca, Peter Schieberle, and Michael Granvogl. "Aroma-active compounds in bartlett pears and their changes during the manufacturing process of bartlett pear brandy." Journal of agricultural and food chemistry 64.50 (2016): 9515-9522]
 {{:pyrus_communis.jpg?600}} \\
 Masclef, A., Atlas des plantes de France, vol.2, t.111 (1890) \\
 [[http://plantgenera.org/species.php?id_species=857515]]
 {{http://www.botanische-spaziergaenge.at/Bilder/Konica_3/PICT3187.JPG}} \\
 Pyrus communis \\ © Rolf Marschner (2006),
 [[http://botanische-spaziergaenge.at/viewtopic.php?f=411&t=1242| www.botanische-spaziergaenge.at]]

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