Volatiles from herbs and spices 197
Gopalakrishnan et al. (1984) characterized six sesquiterpenes namely, a-cubebene
(1.3%), a-copaene (0.4%), a-humulene (9.1%), b-caryophyllene (64.5%), g-cadinene
(2.6%) and d-cadinene (2.6%) in the hydrocarbon fraction of the freshly distilled
Indian clove bud oil. Clove oil from the Malagasy republic was dominated by eugenol
(72–73%), eugenyl acetate (6.3–7.8%) and caryophellene (15.7%) (Lawrence and
Reynolds 1985). The essential oil content ranged from 12.9–18.5% in clove buds and
3.0–7.7% in pedicel. Eugenol content varied from 44–55% in bud oil and 60.0–
72.4% in the oil from pedicel (Zachariah et al. 2005).
Coriander
Coriander oil is clear, colourless to light yellow liquid. Norwegian seeds contain
higher levels of volatile oil (1.4–1.7%) (Purseglove et al. 1981b). Indian coriander
seeds are poor in oil content (0.1–0.4%) (Agrawal and Sharma 1990). The major
component of the essential oil was linalool (67–70%). Kumar et al. (1977) observed
that small-fruited coriander was characterized by high oil content and preferred for
distillation. Large fruited coriander seeds are lower in oil content and are more suited
for use as spice.
Leaf oil of coriander is dominated by decanal (10%) and dodecanals (35%). Indian
coriander oil is lower in linalool content and higher in linalyl acetate (Rao et al.
1925). Coriander seed oil contained 21% linalyl acetate and 42% linalool (Gupta et
al. 1977). Steam distilled oil contained less linalool (71.9%) compared to CO 2 extract
(83.2%) (Hirvi et al. 1986). Boelens et al. (1989) reported that linalool content
(70.4%) was higher by hydrodistillation as against by hydrodiffusion (66.2%) and
organoleptic preference was slightly more for the oil obtained by hydrodiffusion over
hydrodistillation.
Nitz et al. (1992) compared the composition of the distilled oil of coriander with
that of the SFE extract and found that the major compounds were linalool (63%),
limonene (4%), g-terpinene (9%), camphor (4%), a-pinene (8%) and geranyl acetate
(2%). Diederischen (1996) analyzed 237 accessions of fruit oil and the main constituents
Table 11.11 Percentage composition of clove oil
Components Percentage
(E)-b-Ocimene 0.03
Linalool 0.08
Terpinen-4-ol 0.03
Nerol 0.79
Eugenol 94.4
a-Copaene 0.04
b-Caryophyllene 2.91
a-Humulene 0.36
(E.E)-a-Farnesene 0.06
g-Cadinene 0.18
(E)-Nerolidol 0.03
b-Caryophyllene oxide 0.67
Humulene oxode II 0.07
l-Cadinol 0.07
Cadalene 0.18
Hexadecyl acetate 0.09
Source: Raina et al. (2001).