AROMA CHEMICALS : - IFEAT

Six-membered ring compounds are called delta-lactones.
O
O
δ-Decalactone
O
O
Jasmolactone
O
O
δ-2-Decenolactone
(2-Decen-5-olide)
Seven-membered ring types are called epsilon-lactones. Examples of macro-cyclic lactones
include cyclopentadecanolide (pentalide), cyclohexadecanolide and ambrettolide.
O
O
ε-Decalactone
O
O
15-Cyclopentadecanolide
Gamma-lactones, especially gamma-alkyl-gamma-lactones and delta-lactones, especially deltaalkyl-delta-lactones
are the focus here. They are also called gamma- or delta-C number lactone.
The number refers to the number of carbon atoms that constitute the lactone. For example,
gamma-decalactone is constituted from ten carbons, so it is called gamma-C10 lactone.
Lactones in nature
Gamma-alkyl-gamma-lactones and delta-alkyl-delta-lactones are found in various plants, animals
and insects. Table 1 shows the occurrence of 15 lactones, including 9 gamma-lactones and 6 deltalactones,
in peaches 1 .
A map of lactones in nature is shown in Table 2. This is compiled from examination of the BACIS
Computer Database 2 . It reveals that lactones are found in a wide variety of natural foods. This
information is often the starting point when we construct flavors and fragrances.
Odour characteristics of lactones
The odour characteristics of gamma-lactones and delta-lactones are shown in Table 3. The size of
the dots indicates to the comparative strength of an odour note. For example, gamma-C9 lactone
displays four notes : tonka-coumarin, coconut, peach, and floral and the coconut note is dominant.
The sugar-tobacco note exists in gamma-C5, 6, and delta-C8, 9 lactones, and especially in gamma-
C5 lactones.
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