Linalool analysis

Sensory perception is both quaUtative and quantitative. The taste of sucrose and the smell of linalool are two different kinds of sensory perceptions and each of these sensations can have different intensities. Sweet, bitter, salty, fmity, floral, etc, are different flavor quaUties produced by different chemical compounds the intensity of a particular sensory quaUty is deterrnined by the amount of the stimulus present. The saltiness of a sodium chloride solution becomes more intense if more of the salt is added, but its quaUty does not change. However, if hydrochloric acid is substituted for sodium chloride, the flavor quahty is sour not salty. For this reason, quaUty is substitutive, and quantity, intensity, or magnitude is additive (13). The sensory properties of food are generally compHcated, consisting of many different flavor quaUties at different intensities. The first task of sensory analysis is to identify the component quahties and then to determine their various intensities. 

Of the 10 constituents which represent nearly half the oil of neroH, only linalool (10) can be said to contribute direcdy to the characteristic aroma of orange flower oil. In 1977, IFF chemists performed an in-depth analysis of this oil and identified three simple terpenic compounds, each present at less than 0.01%, a-terpenyl methyl ether [1457-68-0] (31), geranyl methyl ether [2565-82-4] (32), andhnalyl methyl ether [60763-44-2] (33) (11). The latter two compounds possess green floral-citms aromas and have been known to perfumery for some time a-terpenyl methyl ether (31) has been called the orange flower ether by IFF chemists owing to its characteristic odor. 

Although most consumers appreciate the fieriness of chile, capsaicinoids are not perceived through odor or taste receptors but through the nociceptive pain receptors described earlier. The compounds in chile fruit that create the flavor and aroma are produced in the fruit wall. Buttery et al. [90] generated vacuum steam distilled oil from green bell pepper macerate, with well over 40 peaks on subsequent GC/MS analysis. Of these peaks, the major flavor compound associated with bell pepper aroma was 2-methoxy-3-isobutylpyrazine (Fig. 8.1). They also reported several monoterpenoids in abundance, limonene, trans- 3-ocimene, and linalool as well as other aliphatic aldehydes and ketones. The flavor composition of dried red bell pepper powder (sweet paprika) extracted with ether identified 44 key peaks by GC/MS [91]. In these dried samples the key compounds were P-ionone and several furanones. The post-harvest processing and the different fruit maturities as well as possible varietal differences are all causes for the different aromatic profiles. 

Redundancy analysis was able to explain 47% of total variance in flavour in relation to the 62 aroma compounds in the flrst two components PLS explained only 36%. Neither method, however, correlated either raspberry ketone or linalool with important aroma notes, suggesting concentrations of flie im ct compounds are not important in determining varietal character. 

Blueberry consists of cultivated highbush blueberries Vaccinium corymbo-sum) and wild lowbush blueberries Vaccinium august ifolium). The aroma of cultivated and wild blueberries is dominated by long-chain alcohols, esters and terpenoids. Forney [43] reported that y-butyrolactone, a-terpineol, 6-ethyl 2,6-decadiene-4,5-diol, linalool, benzaldehyde and 2-ethyl-2-hexenal contribute to the aroma of fresh, whole highbush blueberries using GC-O analysis. In... 

For that reason enantioselective analysis of linalool and linalyl acetate proved to be a powerful tool to detect adulterations with synthetic racemates of linalool and linalyl acetate, respectively [56, 75]. 

A reliable authenticity assessment is concluded from the simultaneous consideration of multielement IRMS and enantioselective analysis. The differences of the stable isotope ratios of linalool and linalyl acetate are depicted as a three-dimensional plot of A values (d values of linalool minus d values of linalyl acetate for oxygen, hydrogen and carbon) (Fig. 17.15). This plot shows that the commercial samples S1-S5 are different from all the other samples investigated. Linalool and linalyl acetate of S1-S5 definitely are not genuine lavender oil compounds. 

Fig. 17.15 Multielement IRMS analysis of lavender oil main compounds. Differential diagram (h = linalool - linalyl acetate ) authentic (black circles) and commercial (white circles) samples commercial non-authentic (circles with a line through) and special aberrations (circles with a cross) [82]...

The biotransformation of linalool by Botrytis cinerea has also been described [60]. After addition of linalool to botrytised must, a series of transformation products was identified (E)- (49) and (Z)-2,6-dimethyl-2,7-octadiene-l,6-diol (48), trans- (76) and cw-furanoid linalool oxide (77), trans- (78) and c/s-pyranoid linalool oxide (79) and their acetates (80, 81), 3,9-epoxy-p-menth-1 -ene (75) and 2-methyl-2-vinyltetrahydrofuran-5-one (66) (unsaturated lactone), Fig. (11). Quantitative analysis however, showed that linalool was predominantly (> 90%) metabolised to ( )-2,6-dimethyl-2,7-octadiene-l,6-diol (49) by B. cinerea. The other compounds were only found as by-products in minor concentrations. 

Fig. 1. (—)-Iinalool attenuates mechanical allodynia induced by spinal nerve ligation in mice. (A and B) Mechanical allodynia developed and maintained over time following spinal nerve ligation (SNL). (A) A single dose of linalool (100 mg/kg s.c.) did not cause any significant changes compared to SNL and vehicle-treated animals. (B) Linalool administered daily for 7 days attenuated mechanical allodynia compared to SNL animals and SNL animals treated with the vehicle ( p < 0.001 vs vehicle ANOVA+Tukey test). Data are expressed as mean SEM of the value corresponding to 50% of pain threshold and are normalized to the basal value of each animal. Differences are evaluated using oneway analysis of variance (ANOVA), followed by post hoc Tukey multiple comparison tests, p < 0.05 was regarded as significant.

Fig. 3. (-)-Linalool does not affect the expression of p-Akt and Akt in the spinal cord of neuropathic mice. (A) Western blot analysis of lumbar spinal cord (L4—L5 segment) 7 days after SNL alone or in combination with linalool (100 mg/kg s.c.) or vehicle treatment Homogenates were from the ipsi(I)-and contra(C)-lateral side of the cord (pool of three animals for each experimental group). (B—D) Densitometric analysis of immunoblots probed with anti-Akt, anti-phospho-Akt (Ser473), and anti-GAPDH antibodies from three different experiments (mean SEM).

Dilution and concentration experiments on samples of dried black pepper berries from India and Malaysia, as well as enantioselec-tive analysis of optically active monoterpenes, indicated ( )-linalool, (-i-)-a-phellandrene, (-)-limonene, myrcene, (-)-a-pinene, 3-methylb-utanal and methylpropanal as the most potent odorants of black pepper. Additionally, 2-iso-propyl-3-methoxypyrazine and 2,3-diethyl-5-methylpyrazine were detected as important odorants of the black pepper sample from Malaysia, which had a mouldy, musty off-flavour (Jagella and Grosch, 1999a). Gamma irradiation was an effective means of decon-... 

Schubert, V. and Mosandl, A. (1 991) Chiral compounds of essential oils. VIII. Stereo differentiation of linalool using multidimensional gas chromatography. Phytochemical Analysis 2, 1 71-1 74. 

Results of detailed GC-MS analysis of these two fractions are reported in Table 17.2 (volatile oil column and waxes column). Anise waxes were formed mainly by n-pentacosane (35.7%), n-heneicosane (25.8%), n-tricosane (10.3%), n-docosane (9.0%) and n-tetracosane (6.2%). Volatile oil contained 94.2% of anethole (cis and trnns). In the oil, estragole (1.4%), limonene (1.7%), linalool (0.3%), two terpineol isomers (0.3%) and linalyl acetate (0.3%) were also present. Caryophyllene (0.5%) and trans-bergamotene (0.7%) were the main compounds among sesquiterpenes. 

The volatiles of fresh leaves, buds, flowers and fruits were isolated by solvent extraction and analysed by capillary gas chromatography-mass spectrometry. Their odour quality was characterized by gas chromatography-olfactometry—mass spectrometry (HRGC-O-MS) and aroma extract dilution analysis (AEDA). In fresh bay leaves, 1,8-cineole was the major component, together with a-terpinyl acetate, sabinene, a-pinene, P-pinene, P-elemene, a-terpineol, linalool and eugenol. Besides 1,8-cineole and the pinenes, the main components in the flowers were a-eudesmol, P-elemene and P-caryophyllene, in the fruits (EJ-P-ocimene and biclyclogermacrene, and... 

For an essential oil such as lavender, the same major components will be present these are linalool, linalyl acetate and 1,8-cineole. This is the qualitative knowledge. The different types of lavender essential oils will contain different amounts of constituent compounds. Spike lavender, Lavandula latifolia, has high amounts of 1,8-cineole (25-37%), while true lavender, Lavandula angustifolia, has very small amounts (0-5%). Lavandula latifolia may contain up to 60% camphor, while Lavandula angustifolia has only up to about 12%. This is quantitative information. A quantitative analysis is needed to help identify different types of oil and can distinguish chemotypes. 

Chemically, all forms contain linalyl acetate, linalool and 1,8-cineole, along with many other compounds. Further analysis of each type reveals their differences in amounts of chemical components. The situation is illustrated by comparing published data for principal constituents and then seeing how these are reinforced by an actual GC chromatogram. This is shown in Table 7.1 the main figure is the published data while figures in brackets are those taken from the GC analysis of actual oil samples (cis- and trans-ocimene are minor hydrocarbon components, but are included as they are often used as markers for the authenticity of lavender oils). In all cases the amounts of compounds in the hybrid (Lavandula intermedia) are in between those of the true (Lavandula angustifolia) and the spike (Lavandula latifolia). 

The French or sweet basil has a high linalool and lower methyl chavicol content with the exotic basil having the highest methyl chavicol content. It is for this reason that the sweet is often preferred for aromatherapy. Principal chemical components found in essential oils of basil include methyl chavicol (22-88%), methyl eugenol (0.3-6%), linalool (1.1 6%), limonene (2.0 4.9%), cis-ocimene (0.2-2.6%) and citronellol (0.6-3.9%). Analysis for a sample of... 

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