Linalool Determination

Angular Rotation Determine as directed under Optical (Specific) Rotation, Appendix IIB, using a 100-rnm tube. Ester Value after Acetylation Determine as directed under Linalool Determination, Appendix VI, using about 2.5 g of the dry acetylated oil, accurately weighed, for the saponification. Calculate the Ester Value after Acetylation by the formula... 

Assay Determine as directed under Linalool Determination, Appendix VI, using about 1.2 g of acetylated sample, accurately weighed. 

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. 

It is well established that the iridoids are derived from two units of mevalonic acid (97), which itself is derived from acetyl-CoA. Mevalonate is also known to be a metabolic product of leucine (172), and the latter is a precursor of the monoterpene linalool (173). Wigfield and Wen (174) pursued the incorporation of leucine into the monoterpene unit in both vindoline (3) and catharanthine (4), where levels of 0.07 and 0.02%, respectively, were found, irrespective of the amount of precursor fed. This was important because, although initial results were obtained with [2- C] leucine, the specificity of incorporation was determined with 2- C-la-beled precursor. Two carbons in vindoline (3), C-8 and C-24, were en-... 

The enantiomeric differentiation of linalool is useful in the quality control of essential oils and oleoresins, as it was found to provide an important indication of the authenticity of many herbs and spices. The enantiomeric composition of linalool has been determined in many essential oils, including basil, bergamot, rosemary, lavandin, lavender, balm, coriander, mace. Pelargonium, rose, Cymbopogon, lemon, mandarin, Osman-thus, davana, jasmine, Lippia alba and orange, as well as in many fruit... 

Chen. Determination of trace germanium in herbal medicine by graphite fur nace atomic absorption spectrometry. Fenxi Shiyanshi 1991 10( 1) 30-31,34-Owuoe, P. O. Differentiation of teas by the variations of linalool and geraniol contents. Bull Chem Soc Ethiopia 1989 3(1) 31-35. 

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. 

The determination of 5 Gv-pdb and d Hv sMow values of synthetic and natural linalool and linalyl acetate using IRMS has been reported by different authors [76-81]. With use of a pyrolysis interface, the determination of isotope... 

Quality standards for some flavor constituents will eventually be developed—linalool for muscats, for example, and perhaps phenethanol for certain types of wine. Kahn and Conner (124) have published a rapid GLC method for phenethanol. It has been suggested (60) that detection of bacterial activity from the presence and amount of minor bacterial byproducts (arabitol, erythritol, and mannitol) may be useful. Based on GLC determination of carbonyls, esters, and higher alcohols, beers were accurately classified into three categories (125). Anthocyanin content has been determined quantitatively by using molar absorbance values for five anthocyanin pigments (126). 

Many essential oils contain esters (mostly acetates) of alcohols of the formulae C10HlsO (borneol, geraniol, terpineol, linalool), C H O (menthol, citronellol), C1SH240 (santalol). When boiled with alcoholic potash, these esters are hydrolysed (saponified) and yield the free alcohol and the potassium salt corresponding with the acid of the ester. Thus, the volatile oils containing esters have saponification numbers, which may be determined in a manner analogous to that used for fatty matters. 

Free Alcohols alone.—In this case the content in free alcohols (borneol, geraniol, terpineol, linalool, menthol, citronellol, santalol, thujyl alcohol) is determined by transforming the alcohols into the corresponding acetates by boiling with acetic anhydride and then determining the saponification number of the acetylated product acetyl saponification number). 

This is obtained from the peel of the fruit of Citrus aurantium (var. dulcis) and is a golden-yellow liquid with an odour of oranges and a sweetish, aromatic taste. It contains limonene (about 90%), linalool, terpineol, nonyl alcohol, decyl aldehyde and esterified caprylic acid. If adulterated with bitter orange cal (q.v.), the latter is detectable by determinations of the sp. gr. at 15°, rotatory power and residue on evaporation (see Oil of Lemon) and by fractional distillation. 

This is obtained from the skins of the fruit of Citrus bergamia and is a greenish or greenish yellow liquid with a peculiar fragrant odour. It contains d-limonene, dipentene linalyl acetate (33-45%) which is the chief constituent determining its value free linalool an odourless stearoptene, termed bergaptene (about 5%) small proportions of fatty, resinous and waxy substances. 

Fig. 32 Multi-sensor system using y-AhOs, y-ALC Dy, CaCC>3 Dy, Zr02 Dy for discriminating and determining pinene, limonene, and linalool...

Fig. 5. Modulation of IL-1/3 spinal content by spinal nerve ligation and (—)-linalool. IL-1/3 content was determined by ELISA in lumbar spinal cord homogenates. Animals were sacrificed at different time points after SNL alone or in combination with linalool (100 mg/kg s.c.) and vehicle treatment (mean SEM from n — 2 3 for each experimental group).

The composition of the volatile oil, which determines the odour and flavour character, has been of particular fascination to chemists. In the unripe fruits and the vegetative parts of the plant, aliphatic aldehydes predominate in the steam-volatile oil and are responsible for the peculiar, fetid-like aroma. On ripening, the fruits acquire a more pleasant and sweet odour and the major constituent of the volatile oil is the monoterpene alcohol, linalool. 

Transfer a 10-mL sample, previously dried with sodium sulfate, into a 125-mL glass-stoppered Erlenmeyer flask previously cooled in an ice bath. Add to the cooled oil 20 mL of dimethyl aniline (monomethyl-free), and mix thoroughly. To the mixture add 8 mL of acetyl chloride and 5 mL of acetic anhydride, cool for several min, permit to stand at room temperature for another 30 min, then immerse the flask in a water bath maintained at 40° 1° for 16 h. Wash the ace-tylated oil with three 75-mL portions of ice water, followed by successive washes with 25-mL portions of 5% sulfuric acid, until the separated acid layer no longer becomes cloudy or emits an odor of dimethyl aniline when made alkaline. After removal of the dimethyl aniline, wash the acetylated oil first with 10 mL of sodium carbonate TS and then with successive portions of water until the washings are neutral to litmus. Finally, dry the acetylated oil with anhydrous sodium sulfate, and proceed as directed for Ester Determination under Esters, this Appendix. Calculate the percentage of linalool (CioHigO) by the equation... 

Note When this method is applied to essential oils containing appreciable amounts of esters, perform an Ester Determination, this appendix, on a sample of the original oil and calculate the percentage of total linalool by the equation... 

Note This entire procedure is applicable only to linalool and linalool-containing oils. It is not intended for the determination of other tertiary alcohols. 

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