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citrus_paradisi [2021/01/11 22:51]
andreas |
citrus_paradisi [2022/04/08 15:11] (aktuell)
andreas |
| "It is important to note in the grapefruit example that the naturally occuring (+)-nootkatone has a threshold of 1ppb, whreas the (-)-enantiomer has a threshold of 1ppm. Hence, any addition of racemic nootkatone can drastically reduce the odour character of a grapefruit oil." \\ | "It is important to note in the grapefruit example that the naturally occuring (+)-nootkatone has a threshold of 1ppb, whreas the (-)-enantiomer has a threshold of 1ppm. Hence, any addition of racemic nootkatone can drastically reduce the odour character of a grapefruit oil." \\ |
| [Swift, Karl AD, ed. Advances in flavours and fragrances: From the sensation to the synthesis. Royal Society of Chemistry, 2007, 80] | [Swift, Karl AD, ed. Advances in flavours and fragrances: From the sensation to the synthesis. Royal Society of Chemistry, 2007, 80] |
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| | "The chemical composition of the essential oil (EO) obtained by solvent-free microwave extraction (SFME) and hydrodistillation (HD) from the peel of grapefruit (Citrus Paradisi. L) was analysed by gas chromatography/mass spectrometry (GC/MS). Totally, twenty-five components were identified in the EO. Limonene was observed as dominant (91.5-88.6%) for two extraction methods, SFME and HD, respectively. β-Pinene (0.8-1.2%), linalool (1.1-0.7%), α-terpinene (0.7-1.0%) and the other minor components were also detected. Disc diffusion method was applied to determine the antibacterial properties of the EO. The results showed that the EO of grapefruit peel had a wide spectrum of antimicrobial activities against Staphylococcus aureus, Enterococcus faecalis, Staphylococcus epidermidis, Escherichia coli, Salmonella typhimurium, Serratia marcescens and Proteus vulgaris, with their inhibition zones ranging from 11 to 53 mm." \\ |
| | [Essential oil composition and antibacterial activity of the grapefruit (Citrus Paradisi. L) peel essential oils obtained by solvent‐free microwave extraction: comparison with hydrodistillation. Uysal, B., Sozmen, F., Aktas, O., Oksal, B. S., Kose, E. O., International Journal of Food Science & Technology, Vol.46(7), 2011, 1455-1461] |
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| "The sesquiterpene ketone [[http://en.wikipedia.org/wiki/Nootkatone|(+)-nootkatone]], which possesses a citrus-like character and a bitter taste, also occurs as a typical constituent in almost all peel oils [of citrus fruits, like lemon peel 0.06%, grapefruit peel 0.5-1.8%, but grapefruit juice oil 3.3% (!)]. Due to its low odor treshold of 800μg/l water, this bicyclic sesquiterpene contributes much to the overall character of an essential oil even at concentrations below 0.001% (10.000ppb). Its enantiomer (-)-nootkatone lacks both the citrus character and the low treshold... The characteristic fresh fruity top-note of grapefruit juice is mainly due to p-menth-1-ene-8-thiol, which is present only in concentrations below 1ppb. [This] Compound has an odor treshold of 0.1ng/l water, ... one of the lowest odor tresholds of all naturall aroma chemicals." \\ | "The sesquiterpene ketone [[http://en.wikipedia.org/wiki/Nootkatone|(+)-nootkatone]], which possesses a citrus-like character and a bitter taste, also occurs as a typical constituent in almost all peel oils [of citrus fruits, like lemon peel 0.06%, grapefruit peel 0.5-1.8%, but grapefruit juice oil 3.3% (!)]. Due to its low odor treshold of 800μg/l water, this bicyclic sesquiterpene contributes much to the overall character of an essential oil even at concentrations below 0.001% (10.000ppb). Its enantiomer (-)-nootkatone lacks both the citrus character and the low treshold... The characteristic fresh fruity top-note of grapefruit juice is mainly due to p-menth-1-ene-8-thiol, which is present only in concentrations below 1ppb. [This] Compound has an odor treshold of 0.1ng/l water, ... one of the lowest odor tresholds of all naturall aroma chemicals." \\ |
| [Scent and Chemistry, Günther Ohloff, Wilhelm Pickenhagen, Philip Kraft, Wiley-VCH, 2012, 222ff] | [Scent and Chemistry, Günther Ohloff, Wilhelm Pickenhagen, Philip Kraft, Wiley-VCH, 2012, 222ff] |
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| "The chemical composition of the essential oil (EO) obtained by solvent-free microwave extraction (SFME) and hydrodistillation (HD) from the peel of grapefruit (Citrus Paradisi. L) was analysed by gas chromatography/mass spectrometry (GC/MS). Totally, twenty-five components were identified in the EO. Limonene was observed as dominant (91.5-88.6%) for two extraction methods, SFME and HD, respectively. β-Pinene (0.8-1.2%), linalool (1.1-0.7%), α-terpinene (0.7-1.0%) and the other minor components were also detected. Disc diffusion method was applied to determine the antibacterial properties of the EO. The results showed that the EO of grapefruit peel had a wide spectrum of antimicrobial activities against Staphylococcus aureus, Enterococcus faecalis, Staphylococcus epidermidis, Escherichia coli, Salmonella typhimurium, Serratia marcescens and Proteus vulgaris, with their inhibition zones ranging from 11 to 53 mm." \\ | "Aroma extract dilution analyses of the aromas of peels and juices of white and pink grapefruits revealed that rotundone, responsible for peppery, spicy, and woody odors, was detected for the first time at high flavor dilution factors of 256-1024. In both juices, rotundone was detected at the highest flavor dilution factor of 1024. Rotundone in grapefruits was quantitated by a stable isotope dilution assay with a newly synthesized deuterium-labeled internal standard, rotundone-d2,3: its levels were 2180 and 1920 ng/kg in white and pink grapefruit peels and 29.6 and 49.8 ng/kg in white and pink grapefruit juices, respectively. On the basis of these results, sensory analysis was performed to assess the effects of rotundone on a white grapefruit juice aroma reconstitute. This sensory analysis revealed that rotundone does not impart a woody odor or affect any of the existing attributes, but increases various attributes, thus confirming that rotundone is indispensable for the aroma of grapefruit juice." \\ |
| [Essential oil composition and antibacterial activity of the grapefruit (Citrus Paradisi. L) peel essential oils obtained by solvent‐free microwave extraction: comparison with hydrodistillation. Uysal, B., Sozmen, F., Aktas, O., Oksal, B. S., Kose, E. O., International Journal of Food Science & Technology, Vol.46(7), 2011, 1455-1461] | [Nakanishi, Akira, et al. "Quantitation of rotundone in grapefruit (Citrus paradisi) peel and juice by stable isotope dilution assay." Journal of agricultural and food chemistry 65.24 (2017): 5026-5033] |
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| {{:citrus_paradisi.jpg?800}} \\ | {{:citrus_paradisi.jpg?800}} \\ |
| Citrus paradisi photo by Jeff Vanuga, USDA Natural Resources Conservation Service, PD ([[https://creativecommons.org/publicdomain/zero/1.0/deed.de|CC0]]) \\ | Citrus paradisi photo by Jeff Vanuga, USDA Natural Resources Conservation Service, PD ([[https://creativecommons.org/publicdomain/zero/1.0/deed.de|CC0]]) \\ |
| [[https://commons.wikimedia.org/wiki/File:NRCSAZ02039_-_Arizona_(361)(NRCS_Photo_Gallery).tif]] | [[https://commons.wikimedia.org/wiki/File:NRCSAZ02039_-_Arizona_(361)(NRCS_Photo_Gallery).tif]] |
