Apr. 2010, Volume 4, No.4 (Serial No.29)
Journal of Chemistry and Chemical Engineering, ISSN 1934-7375, USA
Chemical Composition of Bergamot (Citrus Bergamia
Risso) Essential Oil Obtained by Hydrodistillation
, El Omri Abdelfatteh
, Kachouri Faten
, Casabianca Hervé
and Chaabouni Mohamed
1. Higher Institute of Food Industries of Tunis, 58, Avenue Alain Savary, Tunis 1003, Tunisia
2. National Centre of the Scientific Research, Echangeur de solaize, Vernaison B .P. 22-69390, France
Received: October 9, 2009 / Accepted: October 27, 2009 / Published: April 30, 2010.
Abstract: Peel essential oil of bergamot (Citrus bergamia Risso) growing in Tunisia was separated by hydrodistillation and obtained in
a yield of 9.7%. The oil composition was investigated using GC and GC-MS with two columns HP-1 and HP-Innowax. Fifteen
compounds accounting for 98.52% of the oil were identified. The oil was characterized by high content of limonene (59.21%), linalool
(9.51%) and linalyl acetate (16.83%).
Key words: Citrus bergamia Risso, bergamot peel oil, essential oil composition, limonene, linalyl acetate.
Citrus peel oils are widely used in the perfume and
cosmetic industries. Among them, bergamot (Citrus
bergamia Risso) peel oil is the most valuable essential
oil due to its unique fragrance and freshness. The
essence composed of a volatile part and non-volatile
fraction find application in the cosmetic, pharmace-
utical and food industries [1-3]. In the volatile fraction,
the oxygenated compounds are included in a superior
amount to that contained in other citrus essential oils
extracted from peels. This oxygenated terpene fraction
provides much of the characteristic flavor of bergamot
oil and its high amount makes this citrus essential oil
unique by its fragrance and aroma .
concerning the chemical composition of the peel of
different varieties of citrus have been reviewed [5-9].
The bergamot essential oil produces in Reggio
Calabria, Italy, has been ranked as the highest quality at
the international trading market . In 1994,
Corresponding author: Chaabouni Mohamed Moncef,
professor, research field: Valorization of the natural com-
pounds of origin vegetable. E-mail: chaabouni.medmon-
Mondello et al.  studied the chemical composition
of bergamot essential oil. They detected more than 100
volatile compounds in Italian bergamot oil, of which
linalyl acetate and linalool were predominant in
addition to limonene. In 1995, Giacomo and Mincione
 reviewed this chemical composition.
This study aims to investigate the oil composition of
bergamot peel obtained by hydrodistillation and to
compare it with composition of bergamot essential oil
provided by the Bergamot Consortium of Reggio
Clabria, Italy .
Bergamot fruit was collected in November 2004
from Tunisia. Grated peel (50 g) were mixed with 200
O and subjected to hydrodistillation using
Dean-Stark apparatus (until there was no significant
increased in the volume of oil collection) to give the
following yield (w/w): 9.7%. The oil was dried over
anhydrous sodium sulfate and stored under N
at 4 .
The determination of retention data and the area
percentage of the identified constituents were carried
out on a two GC-FID systems.
Chemical Composition of Bergamot (Citrus Bergamia Risso) Essential Oil Obtained by Hydrodistillation
(1) An Agilent 5890 system equipped with HP-1 (ref
1909 1 Z-115) column (50 × 320 µm, 0.5 µm film
thickness). GC oven temperature was kept at 80 °C for
8 min and programmed to 220 °C at a rate of 2 °C /min.
(2) An Agilent 6890 system equipped with
HP-Innowax (ref 19091 N-216) column (60 m x 320
µm i.d., 0.5 µm film thickness). GC oven temperature
was kept at 60 °C and programmed to 245 °C at a rate
of 2 °C /min, then constant at 250 °C for 20 min.
The split ratio was adjusted to 1/100. The injector
temperature was 250 °C. The FID detector was kept at
250 °C. The carrier gas was helium (1.3 ml/min).
GC-MS analysis was carried out using the first
system, Agilent 5890 equipped with HP-1 column. The
mass spectra was recorded in the electron impact mode
at 70 eV using the aforementioned chromatographic
conditions. Individual components of bergamot peel
essential oil were identified by their retention indices
compared with literature values [13, 14] and their mass
spectra were interpreted on the basis of the WILEY 275
L computer library.
3. Results and Discussion
The compounds identified in the Tunisian Citrus
bergamia peel oil are listed in Table 1. The forty six
identified components constituted 98.52% of the total
oil. GC and GC–MS analysis showed that the oil
consisted of three main groups of constituents named
monoterpenes hydrocarbons, oxygenated monoter-
penes and sesquiterpenes. Bergamot peel oil studied
here contained 66.37% of monoterpenes hydrocarbons
with limonene as the major component (59.21%).
Furthermore, the oil contained 31% oxygenated
monoterpenes, the main components being linalyl
acetate (16.83%) and linalool (9.51%). The oil had
1.15% of sesquiterpenes. The main sesquiterpenes
were β-Bisabolene (0.47%) and Trans α-Bergamotene
Table 1 Chemical composition of peel Citrus bergamia
essential oil from Tunisia.
Compound Percentage HP-1 HP-Innowax
α-Thujene 0.01 924 1028
α-Pinene 0.48 932 1028
Camphene 0.02 945 1074
Sabinene 0.73 966 1126
β-Pinene 4.38 973 1118
Octanal 0.02 979 1273
Myrcene 1.23 981 1163
α-Phellandrene 0.07 993 1163
p-Cymene 0.03 1014 1271
Limonene 59.21 1029 1214
β- Phellandrene 0.14 1029 1219
(Z)-β-Ocimene 0.01 1033 1234
(E)-β-Ocimene 0.05 1037 1251
γ-Terpinene 0.01 1051 1251
(E)-Thujan-4-ol 0.01 1053 1463
(Z)-Linalool Oxide 0.02 1053 1451
(E)-Linalool Oxide 0.03 1072 1463
Terpinène 0.01 1080 1273
Linalool 9.51 1087 1542
(Z)-Limonene Oxide 0.18 1117 1451
(E)-Limonene Oxide 0.06 1124 1463
Citronellal 0.02 1131 1470
Terpinen-4-ol 0.05 1162 1601
α-Terpineol 1.09 1173 1691
Decanal 0.02 1184 1475
Octyl acetate 0.06 1192 1475
Nerol 0.28 1210 1788
Neral 0.28 1214 1681
Geraniol 0.62 1236 1833
Linalyl acetate 16.83 1244 1559
Geranial 0.27 1256 1730
Bornyl acetate 0.01 1270 1589
Terpinen-4-yl acetate 0.33 1287 -
Linalyl propionate 0.08 1331 1606
Citronnellyl acetate 0.18 1333 1681
Neryl acetate 0.4 1342 1721
Geranyl acetate 0.64 1360 1751
β-Bourbonene 0.01 1386 -
Decyl acetate 0.01 1392 -
(Z)-α-Bergamotene 0.02 1411 1574
β-Caryophyllene 0.1 1419 1606
(E)-α-Bergamotene 0.32 1433 1589
(E)-β-Farnesene 0.03 1447 1663
α-Humulene 0.01 1452 1677
γ-Muurolene 0.11 1471 1695
Germacrene D 0.02 1480 1720
Bicyclogermacrene 0.02 1493 1751
β-Bisabolene 0.47 1501 1728
Caryophyllene oxide 0.02 1571 1990
α-Bisabolol 0.01 1669 -
Total (%) 98.52
Chemical Composition of Bergamot (Citrus Bergamia Risso) Essential Oil Obtained by Hydrodistillation
(0.32%). The results obtained were compared with
those reported in the literature (bergamot oil produced
Reggio Calabria in Italy). The proportion of
limonene in bergamot peel essential oil from Tunisia is
high (59.21%) compared with that in essential oil
produced in Reggio Calabria (37.2%). It is know that
the ratio of linalool to linalyl acetate “essence degree”
is one of the quality indices of bergamot essential oil
and affects the aroma of the essence of bergamot. The
value of this ratio is 0.6 in the present work. The mean
ratio of bergamot oil produced in Reggio Calabria has
been reported to be approximately 0.3 .
According to the existing literature the oil of
bergamot peel obtained by cold-pressing consists of
limonene, linalool, linalyl acetate and non volatiles
compounds such as Bergamottin, Bergapten and
Citropten [1, 9]
which may be deleterious.
Pervaporation is reported as an alternative process to
the traditional techniques (steam distillation and
solvent extraction) used nowadays for extraction of
aroma compounds from natural matrixes . The
extraction of essential oil from bergamot fruit with
enzymatic pre-treatment has been studied; the enzymes
have the function to degrade cell membrane and wall
allowing the almost total release of aroma compounds
. Supercritical fluid chromatography was used in
order to investigate the possibility of detoxification of
this essential oil . However, this purification may be
detrimental to the flavor of the oil, since the processed
oil will have a lower content of the oxygenated
terpenes which are responsible for the olfactory
The results of the oil composition obtained by
hydrodistillation showed a high proportion of limonene
(59.21%) and a high ratio of linalool to linalyl acetate
(0.6). This oil presents a good essence degree which is
better than thus of Calabria essential oil obtained by
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