Terpene alcohols detection

Table 11.1). In both cases, (ii)-nerolidol was not detected or found only in traces in the volatile blend, indicating a rapid conversion of this terpene alcohol into DMNT. Despite finding nerolidol synthase activities, the identification of the respective genes involved in DMNT formation has lagged behind. Schnee et al. 

Three other GC analyses now used in authentication, largely for olive and other oils which should not be refined or solvent extracted, are the determination of waxes, aliphatic alcohols, triterpene alcohols (uvaol and erythrodiol), and stigmastadiene and other sterol-dehydration products (EEC, 1991). These analyses are used at present not to detect adulteration with other oils, but with solvent-extracted or refined oils. However, it is possible that, with solvent-extracted oils, wax, aliphatic alcohol and terpene alcohol compositions, could prove useful in differentiating or detecting different oils. 

Tobacco leaf has a complicated chemical composition including a variety of polymers and small molecules. The small molecules from tobacco belong to numerous classes of compounds such as hydrocarbons, terpenes, alcohols, phenols, acids, aldehydes, ketones, quinones, esters, nitriles, sulfur compounds, carbohydrates, amino acids, alkaloids, sterols, isoprenoids [48], Amadori compounds, etc. Some of these compounds were studied by pyrolysis techniques. One example of pyrolytic study is that of cuticular wax of tobacco leaf (green and aged), which was studied by Py-GC/MS [49]. By pyrolysis, some portion of cuticular wax may remain undecomposed. The undecomposed waxes consist of eicosyl tetradecanoate, docosyl octadecanoate, etc. The molecules detected in the wax pyrolysates include hydrocarbons (Cz to C34 with a maximum of occurrence of iso-Czi, normal C31 and anti-iso-C32), alcohols (docosanol, eicosanol), acids (hexadecanoic, hexadecenoic, octadecanoic, etc ). The cuticular wax also contains terpenoids such as a- and p-8,13-duvatriene-1,3-diols. By pyrolysis, some of these compounds are not decomposed and others generate closely related products such as seco-cembranoids (5-isopropyl-8,12-dimethyl-3E,8E,12E,14-pentadecatrien-2-one, 3,7,13-trimethyl-10-isopropyl-2,6,11,13-tetradecatrien-1al) and manols. By pyrolysis, c/s-abienol, (12-Z)- -12,14-dien-8a-ol, generates mainly frans-neo-abienol. 

Essential oils often contain esters of terpene alcohols the most common are the acetates, formates, propionates, etc. The separation of different esters was performed on silica gel layers, using benzene, chloroform, and other similar solvents as mobile phases. AU of the color reactions for terpene alcohols can be used for the detection of their esters. No differences have been observed in the color esters function as a result of their acid nature. 

All the colour reagents described for the terpene alcohols (p. 229) can be used successfully for the normal esters. The molybdophosphoric acid reagent [No. 168] can also be employed. The sensitivity of detection and the colour intensity are about the same. The coloration with the ester does not seem to be related to the acid component. 

According to Schimmel Co. about 97 per cent, of patchouli oil consists of bodies of no value for odour purposes. They have detected the following constituents in patchouli oil benzaldehyde eugenol cinnamic aldehyde a terpenic alcohol of rose-like odour and of undetermined constitution a ketone of caraway odour forming a semi-carbazone melting at 134° to 135° and a base of stupefying odour not yet identified. But as all these bodies are present in traces only it cannot be said that our knowledge of the odour bearers present in patchouli oil is complete. 

The organoleptic character of hydrocarbons has received little attention in spite of the fact that compounds such as hexane or cyclohexane have a detectable odor. Boelens (1974) reported that the members of a panel could not make any distinction between Cj i - to C)5-alkanes and the corresponding aliphatic alcohols. On the contrary, polyunsaturated hydrocarbons possess typical odor qualities and may therefore be important contributors to food flavors (Ohloff, 1978a) but their presence in coffee is limited to aliphatic volatile compounds, such as pentadiene (A.41) and isoprene (A.44), and to 5-methyl-1,3-cyclohexadiene (A.47), not forgetting the terpenes mentioned later. Nevertheless the flavoring power of these paraffins is certainly negligible as compared with the most characteristic constituents of coffee, cocoa, and tea. 

Alkanes, various alcohols, acetates, C2-C4 benzenes, terpenes and derivatives of naphthalene are frequently detected. Many modem floor waxes are based on natural ingredients such as alkyd resins. On oxidative degradation of unsaturated fatty acids, volatile aliphatic aldehydes (C5-C11) of disagreeable smell (Ruth, 1986) are formed. 

The composition of hpids on the surface of leaves, stems, and fruits is quite different from that of hpids that form intracellular membranes. Their role is the protection of sensitive plant tissues against the loss of water and other biologically important volatiles. Waxes (i.e., esters of FA with monofunctional alcohols) are the most important components of these lipids. Some plant waxes are of commercial importance, such as camauba or candellila wax. They are solid at room temperature and in temperate climates, with the exception of liquid jojoba wax, and are plastic or even liquid in tropical climates. They contain bound saturated long-chain FA and alcohols. Waxes on the surface of apples and other fruits from temperate zones are solids or semisolid pastes, consisting of terpenes, ceryl cerotate, ceryl palmitate, and other esters. In the wax from lettuce leaves, higher alcohols prevail, with only small amounts of free FA (Bakker et al., 1998). Other components, such as alkanes, ketones, esters, secondary alcohols, were detected in other vegetables (e.g., in kale or rutabaga). 

Compounds assigned to the wood and biomass combustion category include terpenes and oxygenated pyrolysis products such as aldehydes, alcohols, and ketones [104, 105]. Although simple aromatics have been reported in the literature from residential wood burning, our samples were collected during summer when biomass combustion was minimal. It is more likely that detected aromatic products originate from petroleum residuals. 

Volatile components of natural and roasted hazelnuts have been investigated by several researchers [7,88,90-98]. Among several volatile aroma-active compounds detected in roasted hazelnut, 5-methyl-( )-2-hepten-4-one (fllbertone) has been reported as the primary odorant (nutty-roasty and hazelnutlike) [88,93,94,96]. Alasalvar et al. [98] studied the comparison of natural and roasted Turkish Tombul hazelnuts and found a total of 39 compounds in natural hazelnut and 79 compounds in roasted hazelnut. These included ketones, aldehydes, alcohols, aromatic hydrocarbons, terpenes, furans, pyrroles, pyrazines, and acids. Pyrazines, pyrroles, terpenes, and acids are detected in roasted hazelnut only. The combination of several volatile aroma-active components that increases upon roasting may contribute to the distinctive and unique flavor of roasted hazelnut. Pyrazines together with ketones, aldehydes, furans, and pyrroles may contribute to the characteristic roasted aroma of hazelnut. Detail information about flavor and volatile compounds in major tree nuts are detailed in Chapter 7. 

The free volatile compounds of wines were extracted with dichloromethane. Representative wine aroma extracts for chemical and olfactory analysis were obtained using this solvent. Fig. 1 is the TIC of free volatile compounds of Rojal wines detected by SPE-GC-MS. Quantitative data of the volatile compormds found in free aroma fraction of the young red wines from Rojal grape variety are shown in Tables 1 and 2. The data are expressed as means (pg/1) of the GC-MS analyses of duplicate extractions and they correspond to the average of the analyzed wines. Improvement in the analytical method used to extract the volatile compounds from these wines has allowed us to identify and quantify 80 free volatile compounds in Rojal red wines including alcohols, esters, acids, terpenes, C13 noiisoprenoids, Ce compounds and benzenic compounds. They have been positively identified and quantitatively determined. 

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