Dill ether

Dill weed oil, which is the most important, is obtained by steam distillation from dill weed (herb) before the fruits become mature. Its main constituents are a-phellandrene (10-20%), limonene (30-40%), carvone (30-40%) and the so-called (+)-dill ether [74410-10-9] (up to 10%) [477-485]. The... 

By AEDA the four odorants shown in Figure 9 were detected with the highest FD-factors in dill herb [33], A mixture of these compounds, dissolved in water at the same concentration ratios occurring in the herb (Table 16) very much resembled the typical odor of the dill herb. If (S)-a-phellandrene or the dill ether (B and A Fig. 9), respectively, were omitted, the mixture lost its typical odor note. On the contrary, omission of myristicin and methyl 3-methylbutanoate (D and C Fig. 9) did not significantly influence the overall dill herb aroma of the model mixture [33, 66], The data indicated that (S)-a-phellandrene and the dill ether are the character impact compounds of the dill herb. Since, on the basis of AEDA or calculation of OAVs further odorants have been shown to contribute to the dill herb flavor [33, 66], the results of the simulation experiments revealed that obviously the two monoterpenes are able to mask the flavor contributions of these compounds. 

Main components In the fresh herb 0.5-1.5%, in the dried herb 0.05-0.35% essential oil, which contains up to 40% a-phellandrene, as well as limonene, carvone, and dill furan (dill ether, 3,8-epoxy-p-menth-l-en) as main components [86, 87, 88]. The latter should be present in a minimum of 5% as an indicator of pure herb oil ]89, 90]. 

AEDA and sensory studies show that (S)-a-phellandrene in combination with dill ether generate the aroma of dill herb /SO, 87]. An essential odorant of dill fmits is (S)-carvone, which smells like caraway ]86]. 

Production By steam distillation form dill weed [Anethum graveolens) before die fruit are ripe (seeds). CompositionMajor components are ( )-limonene (see p-menthadienes) (30-40%) and (+)- carvone (30-40%) mainly responsible for the organoleptic impressions are )-a-phellandrene (see p-meiitha-dienes) (10-20%) and (+)-dill ether (CjoHmO, Mr 152.24). CH3... 

Dill ether, xcc E-20073 Dilopholide, D-10264 Dimercaptomethane, see M-20042 Dimerostemmabrasiolidc. in D-10159 /. -Dimethacrylox lhydroquinone. see D-30240... 

Dill weed oil is dominated by a-phellandrene, limonene, and carvone. Dill ether and the absence of dill apiol are further criteria for that oil. Dill seed oil contains mainly carvone and dihydro-carvone. Adulteration is done using phellandrenes, distilled limonene coming from orange terpenes, synthetic carvone, and dihydrocarvone. Detection is done by 2D enantiomeric separation. Lawrence (1996) reports the following ratios for dill seed oil (+)-limonene 98.4% (-)-limonene 1.6% (+)-carvone 98.7% (-)-carvone 1.3% (+)-trans-carveol 33.3% (-)-trans-carveol 66.7% and (+)-cti-carveol 100% (-)-cA-carveol 0%. The authors own ndings from biocultivated oil was (+)-carvone 98.4% (-)-carvone 1.6% (5)-(-)-a-pinene 4.0% (R)-(+)-a-pinene 96.0% (+)-limonene 95.4% (-)-limonene 4.6% (5)-(-)-p-phellandrene 0% (5)-(+) p-phellandrene 100% and (R)-(-)-a-phellandrene 100% (R)-(+)-a-phellandrene 0%. 

A 5-membered oxygen containing heterocycle fused to the cyclohexane ring is the characteristic structure of menthofuran and dill ether. Menthofuran is an atypical compound of pennyroyal oil Mentha pulegium) and appears in small amounts in mint oils. Dill ether is a major compound in the distilled oil from dill herb Anethum graveolens) providing the typical dUl odor. 

AEDA and sensory investigations show that (S)-a-phellandrene in combination with (3S,3aS, 7aR)-3,6-dimethyl-2,3,3a,4,5,7a-hexahy-droben-zo[b]furan (XVIII, dill ether, cf. Formula 22.5) produce the aroma of dill. Both compounds are not stable and are largely lost on drying (Table 22.5). 

An example of terpenic 1,2-epoxides is -caryophyllene oxide, also known as (-)-epoxycaryophyllene (8-31), which occurs in many essential oils. An example of terpenic 1,4-epoxides is the so-called (-l-)-dill ether, (3J ,4S,8S)-3,9-epoxy-p-menth-l-ene (8-31), which is a typical component of the essential oil of caraway (30%) and dill. An example of unsaturated 1,4-epoxides is (-l-)-menthofuran (8-31), the metabolite of ketone (-l-)-pulegone. Both compounds are components of peppermint oil (see Table 8.32, later) and are hepatotoxic. Monoterpenoid compound (- -)-l,8-cineole (also known as limonene oxide, eucalyptol or 1,8-epoxy-p-menthane 8-31) is an example of more complex structures. It is present in essential oils of many types of spices, and higher quantities are found in the essential oil of trees of the genus Eucalyptus (Myrtaceae). Trivial and systematic names of selected ethers are given in Table 8.8. 

Anethum graveolens (+)-Carvone, limonene, (+)-dihydrocarvone, (-)-carveol (seeds) a-phellandrene, (+)-dill ether (haulm)... 

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