close

Вход

Забыли?

вход по аккаунту

?

28

код для вставкиСкачать
Journal of the Science of Food and Agriculture
J Sci Food Agric 79:1954±1957 (1999)
Essential oil of nutmeg pericarp
Li-Cheong Choo, Siew-Meng Wong and Kong-Yong Liew*
School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
Abstract: The composition of the volatile oil extracted by hydro-distillation from nutmeg pericarp and
the component retention indices were determined by gas chromatography±mass spectrometry GC-MS
The oil contains 16 monoterpenes (60%), nine monoterpene alcohols (29%), eight aromatic ethers
(7%), three sesquiterpenes (1%), six esters (1%) and eight other minor components. The components
are similar to those in nutmeg and mace oils but differ substantially in concentrations. The sabinene,
myristicin and safrole concentrations are much lower while the terpinen-4-ol and a-terpineol contents
are much higher than in nutmeg and mace oils.
# 1999 Society of Chemical Industry
Keywords: essential oil; nutmeg pericarp
INTRODUCTION
The nutmeg tree, Myristica fragrans Houttyn, is a leafy
evergreen of height 12 m when mature. The round,
yellowish-green nutmeg fruit, of diameter 4 cm,
consists of the pericarp, the aril and the seed. The
seed and the aril, commonly referred to as nutmeg and
mace respectively, are common spices and are sometimes used in Chinese and other folk medicines for
their abortifacient and therapeutic properties. They
are also known to contain a hallucinogenic principle
and to be toxic.1 The pericarp, 1±2 cm thick, is
usually cut in thick slices or sliced thinly in strips,
treated and coated with thick sugar syrup or honey and
eaten as a ¯avourful candy titbit. It is also treated with
salt water, washed and boiled with syrup to make a
nutmeg concentrate for a refreshing drink.
Nutmeg and mace oils have been analysed since the
last century and their composition and organoleptic
characteristics have been extensively studied. Essentially these oils contain >80% monoterpenes, >5%
monoterpene alcohols, >5% aromatics and other
minor components.2,3 The characteristic ¯avour is
Figure 1. Typical chromatogram of the
essential oil from fresh nutmeg pericarp
extracted by hydro-distillation and
separated on a 50m, 0.2 mm SPB-1
column programmed from 60 to 260°C
at 4 °C minÿ1 using an FID detector.
Peaks with a dot are not identified.
* Correspondence to: Kong-Yong Liew, School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia
(Received 13 November 1998; revised version received 28 May 1999; accepted 18 June 1999)
# 1999 Society of Chemical Industry. J Sci Food Agric 0022±5142/99/$17.50
1954
Essential oil of nutmeg pericarp
Relative retention index (KI) Relative peak area (%) a
Table 1. Composition of nutmeg
pericarp oil
Component
SPB-1
Supelcowax-10
Fresh
Freeze-dried
a-Thujene
a-Pinene
a-Fenchene
Camphene
Sabinene
b-Pinene
b-Myrcene
a-Phellandrene
D3-Carene
a-Terpinene
p-Cymene
Limonene
b-Phellandrene
b-Ocimene
g-Terpinene
Unknown alcohol
Unknown (alkyl aromatics)
a-Terpinolene
Linalool
D-Fenchyl alcohol
cis-p-Menth-2-en-1-ol (?)
Unknown (alcohol)
Unknown (ester)
Terpinen-4-ol
1-Borneol
a-Terpineol
Nerol
Safrole
endo-Bornyl acetate
Eugenol
Citronellyl acetate
Geranyl acetate
b-Citronellol
p-Cymen-8-ol
a-Copaene
Methyl eugenol
trans-Caryophyllene
Isoeugenol
b-Farnesene
Myristicin
Elemicin
2,6-Dimethoxy-4-(2-propenyl)phenol
Methyl isoeugenol
Unknown
t-Muurol (?)
Unknown
Unknown
Three other unknowns
921
926
Ð
943
962
971
982
997
1006
1011
1012
1021
1022
1039
1051
1060
1074
1080
1085
1098
1106
1124
Ð
1168
1170
1180
1218
1264
1270
1329
1333
1359
Ð
Ð
1375
1393
1417
1420
1447
1491
1512
1546
Ð
Ð
Ð
Ð
Ð
Ð
1026
1053
1062
1124
1112
1165
Ð
1147
1181
1274
1202
1210
1255
1248
Ð
1421
1288
1539
1576
1560
Ð
1324
1603
1656
1697
1783
1871
1857
2160
1667
1742
1752
1832
Ð
2004
1595
2338
Ð
2256
2221
2544
2194
2185
2190
2424
2688
0.05
15.2
0.1
0.2
0.4
6.8
3.3
1.9
3.7
3.4
0.7
5.7
5.4
0.1
5.2
0.1
0.4
6.5
1.8
0.4
0.2
0.2
0.1
13.5
0.1
15.5
0.4
1.5
0.1
0.1
0.2
0.05
0.05
0.2
0.1
0.1
0.4
4.5
0.1
1.0
0.2
0.1
0.1
0.2
0.1
0.2
0.4
nd
14.1
0.1
0.1
1.2
9.0
4.1
1.7
1.7
6.1
0.4
4.6
2.8
0.2
9.1
0.2
0.2
5.1
0.7
0.1
0.2
0.1
0.1
19.1
0.1
8.2
0.5
0.8
0.1
0.1
nd
nd
nd
0.2
0.2
0.1
nd
3.1
0.3
3.0
0.1
0.1
nd
0.1
0.2
0.3
0.5
(?), KI values differed from literature values by more than 10 units; Ð, not detected.
a
Average values from two samples,.
said to be due to the presence of myristicin and
elemicin.4 Mace and nutmeg oils contain 1.9% and
0.3% safrole respectively, which has been suspected
to be carcinogenic.5 Although the pericarp is consumed as a food or drink in the countries where
nutmeg is produced, no report on the composition of
the essential oil was found.
J Sci Food Agric 79:1954±1957 (1999)
EXPERIMENTAL
After the seeds and maces were removed from the
mature nutmeg fruits, obtained from a small plantation in Penang Islands, Malaysia, the pericarps were
®nely chopped in a kitchen blender. One half was
freeze-dried in a freeze-dryer (Virtis, Model Unitop
600L) while the rest was used without further
1955
L-C Choo, S-M Wong, K-Y Liew
Pericarp (%) a
Component group
Table 2. Comparison of component groups in
nutmeg pericarp, nutmeg and mace
Monoterpene hydrocarbons
62 (16)
Monoterpene alcohols
29 (9)
Sesquiterpene hydrocarbons
1 (4)
Aromatics
7 (9)
Esters
1 (5)
b
82 (11)
70 (14) c
4.8 (6) b
8.7 (16) c
Ð
1 (9) c
5 (7) b
18 (12) c
1 (2) b
Ð(7) c
Mace (%)
87 (10) d
5.5 (7) d
0.3 (2) d
6.3 (7) d
Ð
Figure in parentheses indicates the number of components in the group.
a
This study.
b
From Ref 2.
c
From Ref 11.
d
From Ref 3.
treatment. Weighed samples were extracted by hydrodistillation or with hexane (Baker Analysed reagent)
for 5 h. The hexane solution was dried by dry
magnesium sulphate and the solvent was removed by
blowing a stream of dry nitrogen until the solvent peak
in the GC trace was less than 1% of the total peak area.
The ®nal yields of the oil were between 2 and 3% of the
dry weight of the pericarps.
The extracted oils were ®rst analysed using a nonpolar and a polar capillary column in a Shimadzu
Model GC-14A gas chromatograph (GC) ®tted with
an FID detector. The non-polar fused silica capillary
column was an SPB-1, column 50 m by 0.2 mm id with
0.33 mm ®lm thickness, operated from 60 to 260 °C at
a heating rate of 4 °C minÿ1. The polar fused silica
capillary column was a Supelcowax-10 column, 30 m
by 0.25 mm id with 0.25 mm ®lm thickness, operated
from 60 to 220 °C at a heating rate of 4 °C minÿ1. The
relative retention indices (KI) of the components were
determined by injecting a reference mixture of C5 to
C32 hydrocarbons into the GC under the same
conditions as for the analysis and calculated according
to the formula given in the literature.6 They were
subsequently analysed using a Hewlett-Packard
5989A GC±mass spectrometer installed with a Wiley
Mass Spectra Library, operated under similar conditions to the GC analysis and an ionisation voltage of
70 eV. The peaks were identi®ed from their mass
spectra in comparison with the spectra in the Library
and con®rmed by comparing their KI values with the
literature values7±10 to within 10 units.
RESULTS AND DISCUSSION
A typical gas chromatogram (Fig 1) of the oil extracted
from the freeze-dried sample by hydro-distillation
consisted of more than 50 peaks depending on the
column used and the concentration of the sample
injected. We were not able to ®nd the KI values for 11
other minor components. The components and their
compositions, based on peak areas, together with their
KI values are shown in Table 1. For the freeze-dried
1956
Nutmeg (%)
sample the 16 monoterpene hydrocarbons constituted
60% of the total area, the nine monoterpene alcohols
constituted 29%, the six aromatic ethers constituted
7%, the three sesquiterpenes constituted 1%, the six
esters constituted 1% and the 11 other minor
components constituted the rest. The compositions
of the oil extracted from the fresh and the freeze-dried
sample did not differ substantially, except that some
minor components not detected in the latter were
detected in the fresh sample.
The compositions of the pericarp oil are substantially different from those of nutmeg and mace oils,
although the components present are similar (Table
2).11 The latter oils both contain more than 80%
monoterpene hydrocarbons with 43% and 14%
sabinene respectively, whereas sabinene is a relatively
minor component in the pericarp oil. Three sesquiterpenes were identi®ed in the pericarp oil in small
concentrations. The monoterpene alcohol content in
the pericarp oil is also much higher than in nutmeg and
mace oils, with terpinen-4-ol and a-terpineol together
contributing 24%. The total concentrations of
aromatic ethers in the three oils do not differ
appreciably. While the myristicin contents in nutmeg
and mace oils were both >3%, the content in the
pericarp oil is much lower at 1%. Although no ill
effects on consumption of nutmeg pericarp titbits or
drinks have been reported, the presence of a large
number of components in the fruit indicates that it
should only be consumed in moderation.
REFERENCES
1 Guenther E, Essential Oils, Vol 5, Van Nostrand Reinhold, New
York, p 78 (1952).
2 Sarah-Kumara SJ, Jansz ER and Dharmadasa HM, Some
physical and chemical characteristics of Sri Lankan nutmeg
oil. J Sci Food Agric 36:93±100 (1985).
3 Forrest JE and Heacock RA, Identi®cation of the major
components of the essential oil of mace. J Chromatogr
69:115±121 (1972).
4 Archer AW, Determination of safrole and myristicin in nutmeg
J Sci Food Agric 79:1954±1957 (1999)
Essential oil of nutmeg pericarp
and mace by high performance liquid chromatography. J
Chromatogr 438:117±121 (1988).
5 Harvey DJ, Examination of the diphenylpropanoids of nutmeg as
their trimethysilyl, triethysilyl and tripropylsilyl derivatives
using combined gas chromatography and mass spectrometry. J
Chromatogr 110:91±102 (1975).
6 Szepesy L, Gas Chromatography, Ileffe Books, London, p 250
(1971).
7 Davis NW, Gas chromatographic retention indices of monoterpenes and sesquiterpenes on methylsilicone and Carbowax
20M phases. J Chromatogr 503:1±24 (1990).
J Sci Food Agric 79:1954±1957 (1999)
8 Analytical Methods Committee, Application of gas liquid
chromatography to the analysis of essential oils, Part XI.
Analyst 109:1344±1357 (1984).
9 Analytical Methods Committee, Application of gas liquid
chromatography to the analysis of essential oils, Part XIV.
Analyst 113:1125±1136 (1988).
10 Baldry J, Dougan J, Matthews WS, Nabney J, Pickering GR and
Robinson FV, Composition and ¯avour of nutmeg oils. Int
Flav Food Additives 7:28±30 (1976).
11 Schenk HP and Lamparsky D, Analysis of nutmeg oil using
chromatographic methods. J Chromatogr 204:391±395 (1981).
1957
Документ
Категория
Без категории
Просмотров
2
Размер файла
63 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа