Carvone, - and

Human perception creates difficulty ia the characterization of flavor people often, if not always, perceive flavors differently due to both psychological and physiological factors. For example, certain aryl thiocarbamates, eg, phenylthiocarbamide, taste exceedingly bitter to some people and are almost tasteless to others (5). This difference is genetically determined, and the frequency of its occurrence differs from one population to another 40% of U.S. Caucasians are nontasters, whereas only 3% of the Korean population caimot perceive the strong bitter taste of the aryl thiocarbamates (6). Similar differences were found ia the sense of smell for compounds such as menthol, carvone, and ethyl butyrate (7). 

The valuable constituent of lliis oil is the carvone, and on this accouDC, and as It is easy to separate Ihis bodv in a fairly pure state, car One is often used in plao ol the oil, and is official in ibe i fidrviifyicpoiia. The result is that ibeve is uiuch de-carvouised oil otv VO),. 1. 20... 

Dihydrocarveol is obtained from both optical forms of carvone, and is optically active in the same sense as the ori nal carvone. It has the following constitution —... 

It is an oil having an odour resembling those of carvone and menthone. Its characters are as follows —... 

The major structural difference between monocyclic and bicyclic compounds should be obvious camphene and camphor exhibit bridged structures. It should be noted, however, that the monocyclic compounds can be further distinguished from each other based on the position of the oxygen atom, located at C-2 in carvone, and at C-3 in pulegone, and in the menthones. Work by others had shown that the... 

The activity of the FePeCli6-S/tert-butyl hydroperoxide (TBHP) catalytic system was studied under mild reaction conditions for the synthesis of three a,p-unsaturated ketones 2-cyclohexen-l-one, carvone and veibenone by allylic oxidation of cyclohexene, hmonene, and a-pinene, respectively. Substrate conversions were higher than 80% and ketone yields decreased in the following order cyclohexen-1-one (47%), verbenone (22%), and carvone (12%). The large amount of oxidized sites of monoterpenes, especially limonene, may be the reason for the lower ketone yield obtained with this substrate. Additional tests snggested that molecular oxygen can act as co-oxidant and alcohol oxidation is an intermediate step in ketone formation. 

Literature examples include one-, two-, and three-step hydrogenation reactions, hi each case, the reactant and product concentrations were monitored, as were intermediates or side reaction products as necessary. Simple peak height or area measurements were sufficient to generate reaction profiles for the reduction of cyclohexene [116] and of l-chloro-2-nitrobenzene [117]. However, for more spectrally complex systems, such as the reduction of carvone and of 2-(4-hydroxyphenyl) propionate, multivariate curve resolution (MCR) was required [117]. 

The major constituent of caraway oil is (+)-carvone, and the typical caraway odour is mainly due to this component. On the other hand, the typical minty smell of spearmint oil is due to its major component, (—)-carvone. These enantiomers are unusual in having quite different smells, i.e. they interact with nasal receptors quite differently. The two enantiomeric forms are shown here in their half-chair conformations. 

The same authors also reported the dehydrogenation of pinocarveol to pino-carvone and pinocampheol to pinocamphone catalyzed by MgO (197) (Scheme 37). Pinocampheol was oxidized to the corresponding ketone with yields in the range of 40%, whereas the yields of pinocarvone from pinocarvenol did not exceed 10%. 

FIGURE 11. Headspace analysis of solutions of menthol [- -], carvone [- -] and cineole [-A-] in SLS (initial concentration, SLS=1.0%, flavorant=0.0075%) showing differences in release of flavor compounds according to their solubility in SLS micelles [Adapted from ref. 77]. 

Spirit drinks which are produced by flavouring ethyl alcohol of agricultural origin with distillates of caraway or dill are called akvavit or aquavit and mainly come from Denmark and Scandinavia these spirits are flavoured using neutral alcohol distillates of caraway (Carvum carvi) and/or dill Anethum graveolens) the use of essential oils is prohibited. The impact compounds of these spirits are f+j-carvone and anethol. 

Given that the concentrations of carvone and piperonal were 0.043 mmol dm and 0.067 mmol dm and that the path length for both spectra was 1 cm, calculate the molar absorptivity (e) for each of the observed absorbances in Problem 2.2. 

The calculated and observed absorbance wavelengths for both carvone and piperonal are in good agreement ... 

As mentioned before, the biotransformation of (+)- and (-)-carvone and other monoterpenoid ketones by yeasts and yeast-like fungi has been reported recently [120]. 

TERPENELESS OIL. An essential oil from which the teqoene components have been removed by extraction and fractionation, either alone or in combination. The optical activity of the oil is thus reduced. The terpene-less grades are much more highly concentrated than the original oil (15—30 times). Removal of terpenes is necessary to inhibit spoilage, particularly of oils derived from citrus sources. O11 atmospheric oxidation the specific terpenes form compounds that impair the value of the oil for example, d-limonene oxidazes to carvone and y-terpinene to p-cymene. Terpeneless grades of citrus oils are commercially available. 

V.p.c. analysis shows contamination by less than 3% of carvone. The checkers used a 1 m. by 4 mm. glass column packed with 5% PEG 6000 on Chromosorb W (60/80 mesh). The retention times were 3.7 minutes and 2.75 minutes for carvone and dihydrocarvone, respectively, at 100° with a nitrogen flow rate of 90 ml. per minute. 

This method is also used for the determination of ketones, such as carvone and pulegone, in caraway and pennyroyal oils.1... 

The determination of aldehydes and ketones is of importance in the analysis of those essential oils characterised especially by aldehydic or ketoruc principles, e g.,the citral contained in lemon and lemongrass oils, citronellal in citronella Oil and some eucalyptus oils, benzaldehyde in bitter almond oil, salicylaldehyde in meadow-sweet oil, anisaldehyde in aniseed and fennel oils, cuminaldehyde m cumin oil, cinnamaldehyde in cinnamon oil, carvone in caraway oil, pulegone in pennyroyal oil and methyl nonyl ketone in rue oil The determination of the aldehydes and ketones presents, however, difficulties and the above methods are moderately exact in only a few cases, especially when the content of aldehydes or ketones is considerable The bisulphite method is applicable particularly to the determination of cinnamaldehyde and benzaldehyde in cinnamon oil and bitter almond oil, and, up to a certain pomt, to that of citral in lemongrass Oil. The sulphite method gives good results in the same cases and for the determination of carvone and pulegone... 

The receptor site for (+)-carvone and (-)-carvone must be chiral such that the... 

Chemat, A., A. Lagha, H. AitAmar, P.V. Bartels and F. Chemcat, Comparison of Conventional and Ultrasound-Assisted Extraction of Carvone and Limonene from Caraway Seeds, Flavour and Fragrance Journal, 19, 188-195 (2004). 

Which of the following properties or methods can be used to distinguish between (R)-carvone and (S)-carvone ... 

R)-Carvone and (S)-carvone are enantiomers and can be distinguished from each other by their optical rotations, by circular dichroism and by smell. Laevorotatory (R)-carvone has a spearmint smell (spearmint = Mentha spicata), whilst (S)-(+)-carvone has a caraway odor. 

Optional) The major essential oil of dill is (+) carvone and the main constituent of spearmint oil is (—) carvone. These are optical isomers. Would the column used in this experiment separate these optical isomers Discuss how you could affect a separation of these two optical isomers using HPLC. 

Since initially neither the stereochemistry of the trisub-stituted double bond nor the absolute configuration of component XVI was known, we prepared all four of the possible geometric and optical isomers starting from either (J3)-(+)-carvone (Figure 6) or (R)-(-)-carvone, and only the 3Z,6R isomer was found to be attractive to the males (48). This is not a practical route to XVI a shorter synthesis of racemic XVI was subsequently published by Still and Mitra (51). 

Major components and compositions of CO2 extracted and distilled spearmint oils are shown in Table 2. A comparison of composition of the produced spearmint oils with the composition of other mint oils (published in the literature [6]) shows that a very special population was investigated. In particular, carvone and its related compounds and pulegone have been found as main components. Gas chromatografic analysis showed significant differences in composition of the SFE products and the distilled oil. The distilled essential oil contained more dihydrocarvone and less pulegone than the CO2 extracted counterpart. 

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