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rheum_rhabarbarum_l [2016/08/17 11:24]
andreas |
rheum_rhabarbarum_l [2021/03/18 10:37] (aktuell)
andreas |
| [[http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=242343402]] | [[http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=242343402]] |
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| "Volatiles of rhubarb (Rheum rhabarbarum L.) stalks were isolated by means of vacuum headspace method and analyzed by capillary gas chromatography−mass spectrometry. Fifty-nine components were reported for the first time in rhubarb. A striking feature of the extracts obtained is the preponderance (∼65%) of compounds with C6 skeletons. In addition to unsaturated C6 aldehydes and alcohols, substantial amounts of the less common (E)-2- and (E)-3-hexenoic acid were detected. Gas chromatography−olfactometry and determination of odor activity values revealed the sensory importance of the C6 compounds to the aroma of rhubarb. Comparative experiments involving the inhibition of enzyme activities revealed that the initial spectrum of C6 components is changed due to subsequent isomerization and reductions. Thus, contributions of (Z)-3-hexenal and the unsaturated acids decrease, and (E)-2-hexenal/(E)-2-hexenol play major sensory roles." \\ | "Volatiles of rhubarb (Rheum rhabarbarum L.) stalks were isolated by means of vacuum headspace method and analyzed by capillary gas chromatography-mass spectrometry. Fifty-nine components were reported for the first time in rhubarb. A striking feature of the extracts obtained is the preponderance (∼65%) of compounds with C6 skeletons. In addition to unsaturated C6 aldehydes and alcohols, substantial amounts of the less common (E)-2- and (E)-3-hexenoic acid were detected. Gas chromatography-olfactometry and determination of odor activity values revealed the sensory importance of the C6 compounds to the aroma of rhubarb. Comparative experiments involving the inhibition of enzyme activities revealed that the initial spectrum of C6 components is changed due to subsequent isomerization and reductions. Thus, contributions of (Z)-3-hexenal and the unsaturated acids decrease, and (E)-2-hexenal/(E)-2-hexenol play major sensory roles." \\ |
| [Volatile constituents of uncooked rhubarb (//Rheum rhabarbarum// L.) stalks. Dregus, M., Engel, K. H., Journal of agricultural and food chemistry, Vol.51(22), 2003, 6530-6536] | [Volatile constituents of uncooked rhubarb (//Rheum rhabarbarum// L.) stalks. Dregus, M., Engel, K. H., Journal of agricultural and food chemistry, Vol.51(22), 2003, 6530-6536] |
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| |{{:hex2enoicacid.jpg|(E)-2-hexenoic acid}} \\ (E)-2-hexenoic acid \\ (cheesy acidic honey)|{{:hex3enoicacid.jpg|(E)-3-hexenoic acid}} \\ [[http://www.thegoodscentscompany.com/data/rw1027611.html|(E)-3-hexenoic acid]] \\ (cheesy fatty fruity)| | |{{:hex2enoicacid.jpg|(E)-2-hexenoic acid}} \\ (E)-2-hexenoic acid \\ (cheesy acidic honey)|{{:hex3enoicacid.jpg|(E)-3-hexenoic acid}} \\ [[http://www.thegoodscentscompany.com/data/rw1027611.html|(E)-3-hexenoic acid]] \\ (cheesy fatty fruity)| {{:methyl2r_butanoicacid.png|(R)-2-methylbutanoic acid}} \\ (R)-2-methylbutanoic acid \\ (cheesy sweat)|{{:methyl2s_butanoicacid.png|(S)-2-methylbutanoic acid}} \\ (S)-2-methylbutanoic acid \\ (pleasant, sweet, fruity)| |
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| Enantiomeric ratios (R:S) of the rhubarb stalk volatiles 2-methylbutanol, 4-methylhexanol, and 2-methylbutanoic acid were on average (80:20), (90:10), and (65:35) respectively. Odours have been described as follows: (S)-2-methylbutanol (ethereal, fresh), (R)-2-methylbutanol (fermented, fatty, musty), (S)-4-methylhexanol (spicy, nutty, slightly green, sour), (R)-4-methylhexanol (green fatty, nut- and carrotlike), (S)-2-methylbutanoic acid (pleasant, sweet, fruity), (R)-2-methylbutanoic acid (cheese, swat), (R)- and (S)-4-methylhexanoic acid (both acidic, fatty). \\ | Enantiomeric ratios (R:S) of the rhubarb stalk volatiles 2-methylbutanol, 4-methylhexanol, and 2-methylbutanoic acid were on average (80:20), (90:10), and (65:35) respectively. Odours have been described as follows: (S)-2-methylbutanol (ethereal, fresh), (R)-2-methylbutanol (fermented, fatty, musty), (S)-4-methylhexanol (spicy, nutty, slightly green, sour), (R)-4-methylhexanol (green fatty, nut- and carrotlike), (S)-2-methylbutanoic acid (pleasant, sweet, fruity), (R)-2-methylbutanoic acid (cheesey, sweat), (R)- and (S)-4-methylhexanoic acid (both acidic, fatty). \\ |
| [Enantioselective analysis of methyl-branched alcohols and acids in rhubarb (Rheum rhabarbarum L.) stalks., Dregus, M., Schmarr, H.G., Takahisa, E., Engel, K.H., Journal of agricultural and food chemistry, 51(24), 2003, 7086-7091] | [Enantioselective analysis of methyl-branched alcohols and acids in rhubarb (Rheum rhabarbarum L.) stalks., Dregus, M., Schmarr, H.G., Takahisa, E., Engel, K.H., Journal of agricultural and food chemistry, 51(24), 2003, 7086-7091] |
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| [Processing and chemical composition of rhubarb (//Rheum rhabarbarum//) juice., Will, F., Dietrich, H., LWT-Food Science and Technology, Vol.50(2), 2013, 673-678] | [Processing and chemical composition of rhubarb (//Rheum rhabarbarum//) juice., Will, F., Dietrich, H., LWT-Food Science and Technology, Vol.50(2), 2013, 673-678] |
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| {{http://plantillustrations.org/ILLUSTRATIONS_HD/82272.jpg?500}} \\ | {{rheum_undulatum.jpg?600}} \\ |
| | Rheum rhabarbarum L. as Rheum undulatum L. \\ |
| Woodville, W., Hooker, W.J., Spratt, G., Medical Botany, 3th edition, vol.5, t.24 (1832) \\ | Woodville, W., Hooker, W.J., Spratt, G., Medical Botany, 3th edition, vol.5, t.24 (1832) \\ |
| [[http://plantillustrations.org/species.php?id_species=874417]] | [[http://plantillustrations.org/species.php?id_species=874417]] |
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| | {{:dsc05624k.jpg}} \\ |
| | Fruiting rhubarb, [[http://www.kraeuterpark.de/|KräuterPark Stolpe]] June 2017, [[https://creativecommons.org/licenses/by-sa/3.0/de/|CC BY-SA 3.0]], Author: Andreas Kraska |
