Aroma linalool

Aroma chemicals are isolates, or chemically treated oils or components of oils. Some components are removed physically, others chemically. In most cases, they are further purified by distillation. For example, Bois de Rose (rosewood) oil may be distilled to isolate linalool, which may be then further treated chemically to yield derivatives such as linalyl acetate, an important fragrance ingredient and a primary component in its own right of lavender and lavandin oils. Vetiver oil Haiti, although containing only 70% alcohols, is treated with acetic anhydride, then carefully distilled to include valuable odor components in the distillate, even though they may not be esters. 

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. 

Linalool has been used to prepare a mixture of terpenes useful for enhancing the aroma or taste of foodstuffs, chewing gums, and perfume compositions. Aqueous citric acid reaction at 100°C converts the linalool (3) to a complex mixture. A few of the components include a-terpineol (34%) (9), Bois de Rose oxide (5.1%) (64), ocimene quintoxide (0.5%) (65), linalool oxide (0.3%) (66), tij -ocimenol (3.28%) (67), and many other alcohols and hydrocarbons (131). 

Procedure The open pistil stigma (Fig. 7C) having a pleasant aroma (like linalool), was treated with allelochemical (the flow of needed solution on... 

Optically pure trans- and czs-linalool oxides, constituents of several plants and fruits, are among the main aroma components of oolong and black tea. These compounds were prepared from 2,3-epoxylinalyl acetate (9) (Scheme 17) [102]. The key step consist of a separation of the diastereomeric mixture of 9 by employing an epoxide hydrolase preparation derived from Rhodococcus sp. NCIMB 11216, yielding the product diol and remaining epoxide in excellent diastereomeric excess (de>98%). Further follow-up chemistry gave both linalool... 

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. 

Solid phase microextraction (SPME) is an ideal approach to monitor volatile flavor components. This approach has been used to identify the volatile compounds in the headspace of fresh fruit during maturation [92], Using SPME fibers and GC/MS, the key flavor components are hexanal, 2-isobutyl-3-methoxypyrazine, 2,3-butanedione, 3-carene, trans-2-hexenal, and linalool (Fig. 8.1). In this study, the principal aroma compounds whose abundance varied during fruit development were specifically identified. 

Bernreuther A, Schreier P, Multidimensional gas chromatography-mass spectrometry A powerful tool for the direct chiral evaluation of aroma compounds in plant tissues, II, Linalool in essential oils and fruits PhytochemAnall. G7— 7(), 1991. 

CS018 Moon, ]. H., N. Watanabe, Y. Ijima, A. Yagi and K. Sakata. Cis-and trans-linalool 3,7-oxides and methyl salicylate glycosides and (Z)-3-hexenyl beta-D-glucopyranoside as aroma precursors from tea leaves of oolong tea. Biosci Biotech Biochem 1996 60(11) 1815-1819. 

Kubota and A. Kobayashi. Optical isomers of linalool and linalool oxides in CS085 tea aroma. Biosci Biotech Biochem 1994 58(1) 2050-2053. 

The "impact compound that provides the primary stimulus for fruit character in the raspberry is the ketone, l-(p-hydroxphenyl)-3-butanone 11). Other important flavour contributors are cw-3-hexen-l-ol, a - and p - ionones, and a - irone (72, 13). In R. arcticus the characteristic aroma is considered to be from mesifiirane (70). It has, however, been reported that steam distillates of raspberries can be assessed for aroma content using a colorimetric procedure and 80% of aroma is accounted for by geraniol, nerol, linalool, a - terpineol and die ionones (13). 

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. 

Acid-catalyzed cyclization and dehydration of citral and linalool give rise to several compounds that occur at comparatively high concentrations and contribute to the typical aroma of distilled lime oil (e.g., 1,4-cineole [470-67-0], 1,8-cineole [470-82-6], 2,2,6-trimethyl-6-vinyltetrahydropyran [7392-19-0], and 2-(2-buten-2-yl)-5,5-dimethyltetrahydrofuran [7416-35-5]) [406-406b, 408-412a]. 

The main component of coriander oil is (+)-linalool (60-80%) [452-460c]. Mono- and polyunsaturated fatty aldehydes, although minor components, contribute to the characteristic aroma of the oil because of their powerful odor. In contrast to the seed oil, coriander leaf oil contains these aldehydes as main constituents, e.g. 2-decenal and 2-dodecenal. 

Approximately 75 volatile compounds have been identified in juices prepared from plums Prunus domestica) [35]. Lactones from Ce to C12 are the major class of compound in plums [78]. The distribution of plum lactones differs from that found in peaches in that the C12 y-lactones are found in higher concentrations than the corresponding Cio y-lactones and d-decalactone (Fig. 7.2) [78]. GC sniffing has uncovered benzaldehyde, linalool, ethyl nonanoate, methyl cin-namate, y-decalactone and d-decalactone as volatile compounds contributing to plum juice aroma (Table 7.2, Figs. 7.1, 7.2, 7.4, 7.5) [35]. 

Approximately 230 volatile compounds have been identified in raspberry fruit [35]. The aroma of raspberries is composed of a mixture of ketones and aldehydes (27%) and terpenoids (30%), alcohols (23%), esters (13%) and furanones (5%). The raspberry ketone (Fig. 7.5) along with a-ionone and jS-ionone have been found to be the primary character-impact compounds in raspberries. Other compounds such as benzyl alcohol, (Z)-3-hexen-l-ol, acetic acid, linalool, geraniol, a-pinene, jS-pinene, a-phellandrene, jS-phellandrene and jS-caryophyllene contribute to the overall aroma of mature red raspberries [101-105]. The most important character-impact compounds of raspberries are summarised in Table 7.3. 

Wild and cultivated blackberries have been used as food and medicine for hundreds of years [106]. Approximately 150 volatiles have been reported from blackberries [107]. The aroma profile is complex, as no single volatile is described as characteristic for blackberry [108, 109]. Several compounds have been suggested as prominent volatiles in blackberries using AEDA, e.g. ethyl hexanoate, ethyl 2-methylbutanoate, ethyl 2-methylpropanoate, 2-heptanone, 2-undecanone, 2-heptanol, 2-methylbutanal, 3-methylbutanal, hexanal, ( )-2-hexenal, furaneol, thiophene, dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, 2-methylthiophene, methional, a-pinene, limonene, linalool, sabinene. 

Important aroma compounds of black currant berries have been identified mainly by GC-O techniques by Latrasse et al. [119], Mikkelsen and Poll [115] and Varming et al. [7] and those of black currant nectar and juice by Iversen et al. [113]. The most important volatile compounds for black currant berry and juice aroma include esters such as 2-methylbutyl acetate, methyl butanoate, ethyl butanoate and ethyl hexanoate with fruity and sweet notes, nonanal, /I-damascenone and several monoterpenes (a-pinene, 1,8-cineole, linalool, ter-pinen-4-ol and a-terpineol) as well as aliphatic ketones (e.g. l-octen-3-one) and sulfur compounds such as 4-methoxy-2-methyl-butanethiol (Table 7.3, Figs. 7.3, 7.4, 7.6). 4-Methoxy-2-methylbutanethiol has a characteristic catty note and is very important to blackcurrant flavour [119]. 

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... 

Banana (Musa sapientum L.) is one of the most common tropical fruits, and one of Central America s most important crops. It is grown in all tropical regions and is one of the oldest known fruits [45]. From a consumer perspective, bananas are nutritious with a pleasant flavour and are widely consumed throughout the world [57]. Esters predominate in the volatile fraction of banana (Fig. 8.2). Acetates are present in high concentrations in the fruit and generally possess a low threshold. Isopentyl acetate and isobutyl acetate are known as the two most important impact compounds of banana aroma. Alcohols are the second most important group of volatiles in banana extracts. 3-Methyl-1-butanol, 2-pentanol, 2-methyl-1-propanol, hexanol, and linalool are the alcohols present in higher concentrations in the fresh fruit [45]. 

In another investigation, linalool (Fig. 8.1) was detected in relatively low concentration in the solvent-extracted volatiles of fresh papaya pulp from Sri Lanka [41]. The authors attributed the characteristic sweaty note of this papaya fruit mainly to methyl butanoate. Phenylacetonitrile was also found in high amounts (17.7%), which, according to the authors, combined with lesser concentrations of benzyl isothiocyanate (1.5%) can play a role in the aroma of papaya. 

More recently, several aroma compounds were isolated from cupuacu pulp by vacuum distillation, solid-phase extraction, and simultaneous steam distil-lation-extarction and were analysed by GC, GC-MS, and GG-O [8]. The olfaction of the extracts obtained by solid-phase extraction indicated linalool, a-ter-pineol, 2-phenylethanol, myrcene, and limonene as contributors of the pleasant floral flavour. In this study, the esters ethyl 2-methylbutanoate, ethyl hexanoate, and butyl butanoate were involved in the typical fruity characteristics. 

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