AROMA CHEMICALS : - IFEAT

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Table 4. Odour characteristics of gamma-lactones 4 (Key : A = 1ppm ; B = 10ppm ; C = 20ppm.) S -isomers γ-lactones R -isomers nearly odorless (B)sweet, caramel (C)sweet, spicy sweet, creamy coconut, with some woody aspects (B)herbaceous fatty, coconut note, with fruity-sweet aspects, less intens than R -isomer (B)coconut, faint sweet, nutty fatty, coconut note less intens than R -isomer (A)coconut (B)coconut, extremely sweet more intense than R -isomer fatty, moldy, weak coconut note less intense than R -isomer coconut, more intense than R -isomer (B)coconut, less intense than R -isomer soft, sweet coconut note with fruity-fatty aspects (B)creamy, peach note fatty-sweet aldehyde note less intense than R -isomer] (A)sweet, caramel (B)sweet, lactone character fatty-fruity, milky note less intense than R -isomer (A)fruity-sweet lactone (B)less intense than R -isomer C5 C6 C7 C8 C9 C10 C11 C12 faint, sweet (B)sweet, caramel (C)sweet, spicy faint, sweet coconut with a fatty herbaceous hay note (B)herbaceous sweet, spicy, herbaceous hay note, reminiscent of coumarin (B)coconut, faint sweet, nutty spicy-green, coconut note, with almond notes (A)coconut (B)coconut, extremely sweet strong, sweet, soft coconut with fatty-milky aspects (A)coconut (B)coconut strong, fatty-sweet fruity note, some reminiscence to coconut, caramel (B)creamy, peach note strong, fatty-sweet, reminiscent of peach, with some bloomy aspects (A)sweet, caramel (B)sweet, lactone character strong, fruity-sweet, bloomy note with aldehyde and woody aspects (A)fruity-sweet, peach, apricot, lactone character (B)sweet peach note Note : • The upper line is for odour appraisal using a solution (1 %, propylene glycol) tested on smelling strip. • The lower line taste appraisal of a solution in invert sugar (10 %) + 0.015 % citric acid. 130
Lactones as aroma chemicals Odour characteristics of chiral lactones Chiral lactones are considered interesting materials for flavors and fragrances, because (R ) and (S) isomers have been shown 4,5 to exhibit different odour characteristics as listed in Tables 4 and 5. Table 5. Odour characteristics of delta-lactones (Ref. 5) S-isomer δ - lactone More fatty,but less intensive coco note C8 Creamy,fruity, nutty, less intensive than (R) antipode. Fruit-sweet,creamy peach note with a fatty, buttery tonality, more intensive than (R) antipode. C10 R-isomer Soft, distinct coco note with spicy-sweet aspects and a weak coumarin–note. Creamy, fruity, nutty. Fruity-sweet, milky note. Similar to (R) antipode, but more intensive. Similar to (R) antipode, but more intensive, with distinct aldehyde and sweet note. Fruity, creamy, more intensive than (R) antipode. C12 Creamy, fruity peach, apricot note. Fruity-sweet, apricot note with fatty-green aspects. Fruity-sweet apricot note. Note : • The upper line describes the odour in a solution (1%, propylene glycol) tested on a smelling strip. • The lower line describes the taste of a 2ppm solution in 10% invert sugar. Chiral lactones in nature The development of chiral chromatography technology has resulted in the discovery of many natural chiral lactones. For example, chiral gamma-lactones in the peach variety ‘hakuhou’ 1 are shown in Table 6. All of the reported lactones, except for gamma-C7 lactone, are rich in the (R)- isomer. Table 6. Chiral lactones in peach “hakuhou” (Ref. 1) lactone ee (%) gamma- hexalactone 63.0(R) gamma- hept alact one 9.2(S) gamma- octalactone 70.2(R) gamma- decalact one 79.8(R) gamma- dodecalactone 89.8(R) delt a- decalact one 96.8(R) Figure 3 (overleaf) shows that in nature the (R)-isomer of chiral delta-decalactone is usually dominant 8 . In cheddar cheese (Figure 4), all of the chiral delta-lactones have a great preponderance of the (R)- isomer. 131
Page 2 and 3: Six-membered ring compounds are cal
Page 4 and 5: Gamma-C9 lactone appears in four no
Page 8 and 9: Figure 3 : Chiral delta-decalactone
Page 10: References 1. Youichi Yamamoto and

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