Aroma compounds linalool

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. 

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. 

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]. 

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. 

As for coriander, 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 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. Sotolon (also known as sotolone, caramel furanone, sugar lactone and fenugreek lactone) is a lactone and an extremely powerful aroma compound and is the major aroma and flavour component of fenugreek seeds (Mazza et al., 2002). 

The free volatiles consist mainly of linalool, geraniol, nerol, furan and pyran forms of the linalool oxides (17, 18, 19a, 20a respectively), a-terpineol, hotrienol 3 and citronellol 4a, which are also the major terpene aroma compounds of the fruit. 

Figure 4.6. The GC/MS-EI (70eV) chromatogram recorded in SCAN mode of free aroma compounds of a Muscat grape skins extract. I.S., internal standard (1-heptanol) peak 1. linalool peak 2.1 rans -p y ra n I i n a I oo I oxide peak 3. cis-pyranhnalool oxide peak 4. nerol peak 5. geraniol peak 6. Ho-diendiol I peak 7. Ho-diendiol II peak 8. hydroxycitronellol peak 9. 7-hydroxy geraniol peak 10. ( )-geranic acid.

The most easily definable hop contribution to beer aroma is a floral flavor note that certain hop varieties (not necessarily the traditional "aroma hop" varieties) impart to beer ( ). Indications are (Table I) that the floral compounds linalool and ger-anlol are responsible for this aroma note. Geranyl isobutyrate, though present in the more floral beers, is probably in too low concentration to have a major effect on beer flavor. a-Terplneol is eliminated from consideration for the same reason. Linalool has been reported in beer at an estimated concentration of 34ppb ( 3) by Lindsay and at a concentration of 470ppb ( 7) by Tressl. 

Recovery of tea aroma compounds (transhexenal, 2-methyl propanal, 3-methylbutanal, phenyl acetaldehyde, benzyl alcohol, linalool, ds-3-hexenol, P-ionone)... 

The main volatile compounds responsible for the fruit aroma are linalool and methyl hexanoate (Franco and Janzantti 2005). 

Dimethyl sulfide has been reported to be an important aroma compound of green tea, along with benzylaldehyde, benzyl alcohol, cyclohexanones, dihydroactinodiolide, cw-hexen-3-ol, hexenyl hexanoate, cis-jasmone, linalool, linalool oxides, nerolidol, and phenylethanol. ... 

Results of this study indicated that eugenol, 1,8-cineol, linalool, and 2-isopropyl-3-methoxypyrazine are characteristic aroma compounds of the essential oil and fresh leaves of O. sanctum. Meanwhile, heating or cooking of fresh herb caused formation of additional thermally derived aroma compounds, such as )S-damascenone and other thermally derived com-... 

Key parsley aroma compounds were recently identified (41). The primary flavor contributors were found to include p-mentha-l,3,8-triene (terpeny, parsleylike), myrcene (metallic, herbaceous), 2-sec-butyl-3-methoxypyrazine (musty, earthy), myristicin (spicy), linalool (coriander), (Z)-6-decenal (green, cucumber), and (Z)-3-hexenal (green). 

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. 

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. 

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). 

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]. 

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. 

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