Characterization of the chemical composition of a byproduct from Siam benzoin gum

Article abstract of DOI:10.1021/jf061193y

The mixture of bark and gum obtained after size-grading of Siam benzoin gum was studied to establish its potential application as a valuable new grade of the balsamic resin. An analysis of its volatile constituents by means of static headspace and SPME led to the identification of 26 and 50 compounds, respectively. Significant differences were observed in both the headspace composition and olfactory properties of the byproduct as compared to those of Siam benzoin gum. This prompted the further analysis of its volatile extract and its resinoid by GC techniques, resulting in the identification of 60 (99.5%) and 16 (89.1%) components, respectively. To examine the influence of bark pieces, different extracts obtained from the raw material and from a sorted sample were analyzed by GC and HPLC techniques. The chemical compositions and the yields determined for the two resinoids lead to the conclusion that this harvesting byproduct is a new grade of Siam benzoin gum, providing interesting olfactory notes that differ from those of other grades.

Full text of DOI:10.1021/jf061193y

8848 J. Agric. Food Chem. 2006, 54, 8848−8854
Characterization of the Chemical Composition of a Byproduct
from Siam Benzoin Gum
†
,†
†
CECILIA CASTEL, XAVIER FERNANDEZ,* LOUISETTE LIZZANI-CUVELIER,
CHRISTINE PERICHET,# AND SOPHIE LAVOINE#
LCMBA, UMR CNRS 6001, Universit e´ de Nice-Sophia Antipolis, Parc Valrose, F-06108 Nice Cedex
2, France, and CHARABOT, Research Natural Products, 10 Avenue Yves-Emmanuel Baudoin,
F-06130 Grasse, France
The mixture of bark and gum obtained after size-grading of Siam benzoin gum was studied to establish
its potential application as a valuable new grade of the balsamic resin. An analysis of its volatile
constituents by means of static headspace and SPME led to the identification of 26 and 50 compounds,
respectively. Significant differences were observed in both the headspace composition and olfactory
properties of the byproduct as compared to those of Siam benzoin gum. This prompted the further
analysis of its volatile extract and its resinoid by GC techniques, resulting in the identification of 60
(99.5%) and 16 (89.1%) components, respectively. To examine the influence of bark pieces, different
extracts obtained from the raw material and from a sorted sample were analyzed by GC and HPLC
techniques. The chemical compositions and the yields determined for the two resinoids lead to the
conclusion that this harvesting byproduct is a new grade of Siam benzoin gum, providing interesting
olfactory notes that differ from those of other grades.
KEYWORDS: Siam benzoin gum byproduct; static headspace; solid-phase microextraction; gas chro-
matography; HPLC
INTRODUCTION
established by SPME and direct GC analysis of its volatile
extracts (7). This work was complemented by an analytical study
of two grades of Siam benzoin gum (grades 3 and 5) using
various headspace sampling methods, which allowed the
identification of 42 volatile and semivolatile compounds (8).
The aim of this study was to determine whether this gum
byproduct could be considered as a new grade of Siam benzoin
gum or as a new raw material. For this purpose, both chemical
and olfactory properties of the byproduct were examined.
Siam benzoin gum is a balsam obtained from Styrax tonki-
nensis that is produced mainly in Laos (1, 2). It is extensively
used in the flavor and fragrance industry owing to its sweet
balsamic odor with a distinct note of vanilla (3). The gum does
not exude naturally from the tree, but is rather a pathological
product resulting from incisions made through the bark. After
the gum flows out and hardens upon exposure to air, it is
harvested by scraping the trunk. This resin is then sorted and
graded according to the size of the pieces (1, 3). Five different
grades providing slightly different olfactory properties can be
found in the trade, from grade 1 (largest pieces) to grade 5,
which contains dust and small amounts of bark. The product
remaining after sorting is a mixture of bark and gum and often
represents >10% of the total harvested benzoin gum by weight.
To the best of our knowledge, this harvesting byproduct has
not yet been exploited, and its chemical composition has never
before been reported.
MATERIALS AND METHODS
Materials. The gum byproduct was provided by AGROFOREX Co.
(Vientiane, Laos). It was obtained from the grading process of Siam
benzoin gum harvested on Styrax tonkinensis trees in northern Laos at
the end of 2002.
Headspace Solid-Phase Microextraction. A manual SPME device
and divinylbenzene/carboxen/polydimethylsiloxane fibers (DVB/CAR/
PDMS; 50/30 µm) were purchased from Supelco. The fiber was
conditioned as recommended by the manufacturer prior to use. Ten
grams of crushed byproduct was placed in a 40 mL amber vial closed
by a PTFE/silicone septum (Supelco). Before extraction, the headspace
in the vial was equilibrated overnight at room temperature. Extraction
was performed at room temperature with a sampling time of 40 min.
After exposure, the fiber was thermally desorbed into the GC injection
port (equipped with a 0.75 mm i.d. inlet liner) for 4 min. The injector
was set at 250 °C and used in the splitless mode. Before any other
sampling, the fiber was reconditioned for 5 min in the GC injection
port at 250 °C.
Siam benzoin gum has previously been described as contain-
ing coniferyl benzoate (65-75%), p-coumaryl benzoate (10-
1
5%), cinnamyl cinnamate (0.5-6%), benzoic acid (12%),
vanillin (0.3%), and siaresinolic acid (6%) (4-6). We recently
reported the chemical composition of Siam benzoin gum as
*
Author to whom correspondence should be addressed (e-mail
xavier.fernandez@unice.fr; telephone +33492076469; fax +33492076125).
†
Universit e´ de Nice-Sophia Antipolis.
CHARABOT.
#
1
0.1021/jf061193y CCC: $33.50
© 2006 American Chemical Society
Published on Web 10/25/2006

Chemical Composition of Siam Benzoin Gum Byproduct
J. Agric. Food Chem., Vol. 54, No. 23, 2006 8849
Static Headspace. The byproduct was extracted using a Hewlett-
Packard 7694 static headspace autosampler (Agilent Technologies). The
headspace sampler was operated as follows: oven temperature, 110
(120 min). The resinoids (10% ethanolic solutions) were analyzed using
the same conditions in splitless mode.
HPLC-UV. HPLC analyses were performed on a Varian ProStar
system equipped with a ProStar 320 UV-vis detector. The column
was a 250 × 4.0 mm HyPurity C18 (5 µm) (Thermo Electron Corp.)
with a 10 × 4.0 mm HyPurity C18 precolumn and was used at room
temperature. Analyses were performed at 254 nm. The column was
eluted with a flow rate of 0.55 mL/min, and the composition of the
mobile phase consisted of water (A) and methanol (B), both containing
0.1% formic acid. The gradient conditions were as follows: 0-10 min,
50% B; 10-11 min, 50-70% B; 11-21 min, 70% B; 21-22 min,
°C; loop temperature, 130 °C; transfer line temperature, 150 °C; sample
equilibration time, 120 min. Eight grams of crushed byproduct was
placed in a 20 mL vial (Agilent Technologies) that was tightly closed
with a PTFE/white silicone septum and a cap. The injection loop
(volume, 3 mL) was filled by depressurizing the headspace for 0.3 min,
and the loop was swept with the carrier gas (loop equilibration, 0.05
min; sample injection, 0.5 min) to inject the volatile components into
the chromatograph via a transfer line (splitless mode).
7
8
8
0-75% B; 22-32 min, 75% B; 32-33 min, 75-80% B; 33-38 min,
0% B; 38-39 min, 80-85% B; 39-44 min, 85% B; 44-45 min,
5-90% B; 45-55 min, 90% B; 55-56 min, 90-100% B; 56-66
Toluene and Styrene Quantification. Toluene and styrene quan-
tification was carried out by external calibration using static headspace
GC. One gram of benzyl alcohol (Aldrich, 108006) was added to 1 g
of crushed raw material in a 10 mL vial (Agilent Technologies) that
was sealed with a PTFE/white silicone septum and a cap. A Combi
PAL autosampler equipped with an incubator oven was used. The
extraction conditions were as follows: oven temperature, 70 °C; sample
equilibration time, 20 min. A 1 mL gas syringe heated at 140 °C was
used for headspace extraction, and the volatile components were injected
into the injection port of an Agilent 6890N gas chromatograph equipped
with a flame ionization detector. The GC was equipped with a HP1
fused-silica capillary column (polydimethylsiloxane, 50 m × 0.2 mm
i.d.; film thickness, 0.33 µm) and used under the following operating
conditions: carrier gas, helium; constant flow, 1 mL/min; injector and
detector temperatures, 250 °C; split ratio, 1/10; temperature program,
min, 100% B. Samples (concentration, 2 mg/mL) were prepared in
methanol, and the injection volume was 20 µL.
Component Identification. Identification of the constituents was based
on computer matching against commercial libraries (Wiley, MassFinder
2.1 Library, NIST98) and a homemade mass spectra library built using
pure substances and MS literature data (9-14). Several structures were
also confirmed by standard compound injection.
Identification of the components was also based on their GC retention
indices (RI) determined on an apolar HP1 column using a homologous
series of n-alkanes (C -C28) (extraction times used for headspace
5
experiments: Static-HS, 30 s at 110 °C; HS-SPME, 20 s at 40 °C).
Chemicals. Most of the standard compounds were purchased from
chemical supply companies. Ethyl benzoate, allyl benzoate, propyl
benzoate, isobutyl benzoate, isoamyl benzoate, 3-methylbut-3-enyl
benzoate, prenyl benzoate, hexyl benzoate, benzyl benzoate, and
cinnamyl benzoate were obtained by reaction of benzoyl chloride with
the corresponding alcohols. R-Terpinyl acetate and neryl acetate were
obtained by reaction between acetyl chloride and the corresponding
alcohols. Benzyl formate was obtained by reaction between formic acid
and benzyl alcohol. Standard procedures were used (15, 16), and
products were characterized by GC-MS (electronic ionization, 70 eV).
Synthesis of (E)-Coniferyl Ethyl Ether. Thionyl chloride (15 mmol)
was added to an ice-cooled solution of 10 mmol of ferulic acid in
absolute ethanol (20 mL). The mixture was refluxed overnight and the
solvent evaporated. A saturated potassium carbonate solution was added
until neutral pH was reached. The aqueous layer was extracted with
diethyl ether; the organic phases were collected and dried over
magnesium sulfate. The solvent was evaporated under vacuum, and
the crude yellow oil was then purified on silica gel to afford crystallized
6
0 °C (4 min) to 110 °C at 2 °C/min then 110 to 250 °C at 20 °C/min.
Volatile Extracts. Volatile extracts were obtained by hydrodistil-
lation using a Clevenger type apparatus for 4 h with 5 mL of pentane
as a recovery solvent, which was evaporated under a slight nitrogen
stream after collection. The yields obtained were 0.01% for volatile
extract 1 (made from the raw byproduct) and 0.03% for volatile extract
2
(made from bark manually isolated from the byproduct).
Resinoids. Resinoids 1 and 2 were obtained from the byproduct and
bark, respectively. One hundred grams of each material was refluxed
in 500 mL of ethanol for 4 h. After filtration and solvent evaporation,
the resinoids were obtained in 63% (resinoid 1) and 14% (resinoid 2)
yields.
Siam benzoin gum (grade 3) resinoid was supplied by CHARABOT
S.A. (Grasse, France). This commercial extract was industrially made
under conditions similar to those described for the above-mentioned
resinoids.
1
13
Chemical Analysis. Headspace Analyses. GC-FID and GC-MS
analyses using headspace methods were carried out with an Agilent
ethyl ferulate in 90% yield (characterized by H, C NMR, and GC-
MS). Ethyl ferulate (10 mmol) was then reduced by diisobutylaluminum
hydride (4.2 equiv) (17), and the coniferyl alcohol obtained was
crystallized from a dichloromethane/petroleum ether mixture (97%
yield). Five milliliters of ethanol was added to 1 mmol of coniferyl
alcohol, and the mixture was refluxed for 5 days to reach a sufficient
conversion; (E)-coniferyl ethyl ether was obtained after purification
on a silica gel column (70/30 petroleum ether/diethyl ether) in 10%
6
890N gas chromatograph equipped with a flame ionization detector
and coupled to an Agilent 5973N mass spectrometer. The GC was
equipped with a HP1 fused-silica capillary column (polydimethylsi-
loxane, 50 m × 0.2 mm i.d.; film thickness, 0.33 µm) and used under
the following operating conditions: carrier gas, helium; constant
pressure, 282 kPa; initial flow, 1.35 mL/min; injector and detector
temperatures, 250 °C; temperature program, 60 °C (4 min) to 250 °C
at 2 °C/min then held isothermal (30 min); ion source temperature,
yield: 1H NMR (200 MHz; CDCl
3.55 (q, 2H, J ) 7 Hz, CH CH ), 3.88 (s, 3H, OCH
) 1.3, 6.2 Hz, CHdCHsCH ), 5.73 (s, 1H, OH), 6.15 (dt, 1H, J )
6.2, 15.8 Hz, CHdCHsCH ), 6.52 (d, 1H, J ) 15.8 Hz, CHdCHs
) δ 1.25 (t, 3H, J ) 7 Hz, CH
), 4.12 (dd, 2H, J
3
2 3
CH ),
2
3
3
2
30 °C; transfer line temperature, 280 °C; ionization energy, 70 eV;
2
electron ionization mass spectra were acquired over the mass range of
2
1
3
3
5-400 amu.
CH
2
), 6.8-7.0 (m, 3Harom); C NMR (50 MHz; CDCl ) δ 15.21, 55.83,
3
6
1
1
5.59, 71.32, 108.27, 114.36, 120.35, 123.94, 129.36, 132.31, 145.51,
Extract Analyses. Volatile extracts were analyzed by GC-MS using
46.58; EI-MS, m/z (%) 77 (26), 91 (84), 103 (54), 119 (89), 131 (100),
a Hewlett-Packard 5890/5970A system, equipped with a HP1 fused-
silica capillary column HP1 (polydimethylsiloxane, 50 m × 0.20 mm;
film thickness, 0.5 µm) and used under the following operating
conditions: carrier gas, helium; injector temperature, 230 °C; split ratio,
•
+
47 (27), 151 (37), 163 (24), 179 (26), 208 (M , 87).
RESULTS AND DISCUSSION
1
/100; temperature program, 60 to 250 °C at 2 °C/min then held
Headspace Sampling Methods. In a previous study (8), HS-
SPME using a DVB/CAR/PDMS fiber allowed us to identify a
large number of volatile compounds in Siam benzoin gum.
However, because the volatile constituents have different
affinities toward the fiber coating, this technique does not readily
allow a quantitative comparison of different samples (18). In
contrast, the use of the S-HS method has enabled us to compare
a large variety of samples on the basis of their respective
headspace compositions.
isothermal (120 min); ion source temperature, 230 °C; transfer line
temperature, 280 °C; ionization energy, 70 eV; electron ionization mass
spectra were acquired over the mass range of 35-400 amu. GC-FID
analyses were carried out using an Agilent 6890N gas chromatograph
equipped with a HP1 fused-silica capillary column (polydimethylsi-
loxane, 50 m × 0.20 mm; film thickness, 0.5 µm) and used under the
following operating conditions: carrier gas, helium; constant flow, 1
mL/min; injector and detector temperatures, 250 °C; split ratio, 1/10;
temperature program, 60 to 230 °C at 2 °C/min then held isothermal

8850 J. Agric. Food Chem., Vol. 54, No. 23, 2006
Castel et al.
In the present work, these two headspace sampling methods
byproduct was described as providing a strong vanilla character
and to be sweeter, less ambery, and less powdery than the resin
due to a weaker benzoic acid note, but giving, in contrast, a
pungent acetic acid note.
optimized elsewhere (8) (fiber, temperature, exposure time) were
used to qualitatively compare the byproduct and commercial
Siam benzoin gum (grade 3). For each headspace sampling
method, experiments were replicated three times. For both the
byproduct and Siam benzoin gum (8), compounds were identi-
fied by GC-RI, GC-MS, and injection of standard compounds.
Relative percentages obtained by direct integration and retention
indices are listed in Table 1.
The S-HS method was used to compare the headspace
composition of the byproduct to that of the gum and led to the
identification of 26 constituents in the byproduct headspace that
represented 99.7% of the total GC-FID area. Among these
components, we observed six monoterpene hydrocarbons
Natural raw materials such as resins, oleoresins, and balsams
are usually used in the flavor and fragrance industry to
manufacture two types of products: volatile extracts (or essential
oils) and resinoids. As a result, both types of extracts were
produced from this harvesting byproduct. In addition, to further
investigate the influence of bark, these extracts were produced
from both the raw material and pieces of bark that had been
manually separated from the remaining resin.
Volatile Extracts. Volatile extracts were obtained by hydro-
distillation of the raw material (VE1) and of the sorted byproduct
(
(
(
∼11.1%), one sesquiterpene hydrocarbon (0.3%), seven esters
∼23.9%), four aldehydes (∼41.5%), and eight other compounds
∼23.9%). The main constituents that characterized the byprod-
(VE2). Due to very low yields of the volatile fractions, it was
necessary to use a recovery solvent during extraction. GC-FID
and GC-MS analyses led to the identification of 60 and 74
compounds in VE1 and VE2, respectively, representing 99.5
and 99.8% of the total FID area (Table 2). These analyses
revealed that VE1 and VE2 contained 5 (∼0.3%) and 9 (∼1.1%)
monoterpene hydrocarbons, 5 (∼2.1%), and 8 (7.2%) oxygen-
ated monoterpenes, 5 (trace level) and 11 (0.2%) sesquiterpene
hydrocarbons, 18 (∼80.9 and 72.9%) esters, 11 (∼13.2%), and
uct were benzaldehyde and R-pinene (32.7%; coeluted), methyl
benzoate (16.7%), and toluene (13.5%). These compounds were
also identified as major volatile components in Siam benzoin
gum. In contrast, the headspace of the byproduct also contained
hexanal (6.9%), furfural (1.9%), â-myrcene (3.0%), and terpi-
nolene (2.8%), none of which were identified in the resin.
SPME-GC-MS and SPME-GC-FID analyses allowed us to
identify 50 compounds in the byproduct headspace representing
9.4% of the total FID area. Thirteen monoterpene hydrocarbons
9
(∼13.6%) aldehydes, and 16 (∼3.0%) and 19 (∼4.8%) other
compounds, respectively. The main components were deter-
mined to be benzyl benzoate (39.8 and 41.7% for VE1 and VE2,
respectively), allyl benzoate (19.8 and 11.5%), methyl benzoate
9
(
∼23.8%), 2 oxygenated monoterpenes (9.6%), 8 sesquiterpene
hydrocarbons (5.0%), 6 esters (23.3%), 6 aldehydes (∼17.7%),
and 15 other constituents (∼20.0%) were observed. The main
components were linalyl acetate (17.9%), benzaldehyde and
R-pinene (14.4%), linalool (8.5%), limonene and â-phellandrene
(17.3 and 15.4%), benzaldehyde and R-pinene (9.6 and 12.6%),
linalool (1.5 and 4.4%), decen-2-(E)-al (2.3 and 0.1%), and ethyl
benzoate (1.5 and 0.8%). The two volatile extracts presented
the same five major compounds, although their overall composi-
tions were quite different. As previously mentioned for the
headspace compositions, the number and the amount of terpe-
noids were higher in VE2 (28 terpenoids representing about
8.5% of the total FID area) than in VE1 (15 terpenoids
representing about 2.4%). In addition, the amount of benzoic
esters was smaller in VE2 (70.6%) than in VE1 (80.1%). As a
result, the comparison of these two volatile extracts allowed us
to confirm that most of the monoterpene components came
directly from the bark.
(
(
8.3%), â-myrcene (5.6%), benzyl alcohol (5.2%), and toluene
3.9%).
Athough a quantitative comparison of the samples by SPME
analysis is not relevant, this technique allowed us to easily
distinguish the byproduct from Siam benzoin gum. The presence
of acetic acid and â-myrcene is representative of the byproduct.
It is reasonable to assume that these two compounds are
precursors of numerous monoterpene hydrocarbons [e.g., (Z)-
and (E)-â-ocimene] and monoterpene acetates (linalyl, neryl,
and geranyl acetate) or alcohols (linalool) not previously
identified in commercial Siam benzoin gum.
In summary, the combination of these two headspace
sampling methods resulted in the identification of 58 volatile
compounds that allowed us to easily distinguish the byproduct
from Siam benzoin gum. Accordingly, it is assumed that the
numerous monoterpene compounds and aldehydes identified
came directly from the bark.
We also detected large amounts of toluene and styrene in
both the byproduct headspace (13.5 and 2.6%, respectively) and
that of Siam benzoin gum (5.2 and 1.0%). This observation led
us to quantify these compounds in the raw materials. The
quantification was carried out by means of static headspace GC
using an external calibration, with benzyl alcohol as the sample
dilution solvent. Toluene concentrations of 3 and 1 ppm were
measured in the byproduct and Siam benzoin gum, respectively.
Only trace levels of styrene (<1 ppm) were detected in the raw
materials. The amount of toluene in both the byproduct and the
gum were below the level authorized for pharmaceutical
products (19). As a result, the concentrations determined for
both compounds do not preclude any further application of the
byproduct in the field of flavor and fragrance.
Resinoids. Resinoids were obtained by ethanol extraction
from the raw material (R1) and the sorted byproduct (R2) in
63 and 14% yields, respectively. R1 and R2 were investigated
by GC techniques, and the results are summarized in Table 2.
GC-FID and GC-MS analyses led to the identification of 16
and 15 compounds in R1 and R2, respectively, representing 89.1
and 83.5% of the total FID area. The major components
identified were benzoic acid (42.6 and 28.6%), coniferyl ethyl
ether (19.0 and 6.1%), vanillin (10.6 and 22.1%), benzyl
benzoate (4.6%), and 2-propiovanillone (4.1 and 4.7%). Several
compounds presenting higher retention indices were not clearly
identified, but their mass spectra corresponded to aromatic ester
structures. The byproduct (R1) and sorted byproduct (R2)
resinoids were closely similar in their compositions, because
the same major components were identified. However, the
amounts of some components, such as benzoic acid and
coniferyl ethyl ether, were higher in R1 than in R2. In contrast,
the content of vanillin was lower in R1 than in R2.
We assumed that the unusual presence of coniferyl ethyl ether
was due to the reaction of ethanol with coniferyl derivatives
during the extraction process. To confirm this, coniferyl alcohol
obtained by the reduction of ethyl ferulate (17) was refluxed in
ethanol, and we were able to observe the formation of
(E)-coniferyl ethyl ether in the reaction mixture. This compound
Next, the olfactory properties of the byproduct were estab-
lished and compared to those of Siam benzoin gum. The

Chemical Composition of Siam Benzoin Gum Byproduct
J. Agric. Food Chem., Vol. 54, No. 23, 2006 8851
Table 1. Headspace Studies of the Crushed Byproduct and Siam Benzoin Gum
SPME
static-HS
compounda
RIb
byproduct %
±
SDc
Siam 3 %
±
SDc
byproduct %
±
SDc
Siam 3 %
±
SDc
identification methodsd
ethanol
0.6
±
0.1
MS, Std
MS, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
formic acid
acetic acid
toluene
hexanal
furfural
p-xylene
styrene
heptanal
benzaldehyde
0.6
1.8
1.7
0.3
±
±
±
0.2
0.1
0.5
566
750
772
800
853
872
874
933
3.4
3.9
2.1
±
±
±
0.3
0.4
0.3
13.5
6.9
1.9
±
±
±
2.4
1.7
1.2
5.2
1.0
±
±
0.2
0.5
e
0.4
0.3
0.2
±
±
±
0.1
0.3
0.1
MS, RI
2.6
±
±
2.6
MS, RI, Std
MS, RI, Std
MS, RI, Std
21.9
6.6
0.3
±
±
±
2.2
0.9
0.3
1
4.4
±
1.6*
32.7
1.0*
46.8
2.1
±
±
2.3*
1.3
R
-pinene
-pinene
-pentylfuran
-myrcene
,3,5-trimethylbenzene
-phellandrene
â
970
975
978
979
997
0.2
0.2
5.6
0.3
0.5
0.3
5.2
0.8
1.9
±
±
±
0.2
0.1
0.1
MS, RI, Std
MS, RI
MS, RI, Std
MS, RI
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
e
2
â
1
3.0
4.8
±
±
±
1.2
1.3
0.4
e
R
±
±
±
±
±
0.3
0.1
0.3
0.1
0.1
decane
1000
1004
1009
1017
1015
1018
1021
1022
1030
1032
1044
1049
1058
1069
1079
1082
1085
1089
1100
1101
1104
1112
1134
1145
1148
1158
1169
1226
1230
1231
1243
1247
1300
1308
1326
1328
1336
1350
1354
1365
1379
1385
1387
1400
1414
1421
1429
1448
1475
1478
1488
1490
1498
1509
1520
1723
benzyl alcohol
6.7
±
±
±
0.4
0.1
0.1
6.9
±
±
0.2*,†
0.3*
R
-terpinene
p-cymene
,8-cineole
limonene
-phellandrene
Z)- -ocimene
acetophenone
0.7
0.2
0.2
1
5.5
2.6
0.7
8.3
±
±
3.5*
0.1
e
â
(
MS, RI
â
2.1
±
±
±
0.3
1.6*
0.2
MS, RI, Std
MS, RI, Std
MS, RI
2.0
e
(
E)-
benzyl formate
-terpinene
guaiacol
,4-diethylbenzene
â
-ocimene
2.6
±
0.2
1.6
±
±
0.2
1.1
1.6
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI
3.7
±
±
0.3*
0.3
γ
0.3
1.5
0.4
1.2
1.4
0.2
8.5
0.1
0.3
0.5
0.3
0.4
2.1
2.6
0.2
1.1
±
0.1
1.5
±
0.1
0.6
1
terpinolene
methyl benzoate
nonanal
linalool
undecane
±
±
0.1
0.1
2.8
16.7
±
±
0.6
1.6
27.7
17.5
0.5
±
±
1.3
0.2
±
±
±
±
0.7
0.1
0.1
0.1
0.3
±
0.1
1
1
,2,4,5-tetramethylbenzene
,2,3,5-tetramethylbenzene
e
e
allo-ocimene
unknown 1
ethyl benzoate
benzoic acid
unknown 2
MS, RI
f
±
±
±
±
±
0.1
0.1
0.5
0.1
0.1
2.3
15.3
±
±
0.2
0.7
0.8
-
±
0.3
2.6
0.8
±
±
0.3
0.1
MS, RI, Std
MS, RI, Std
f
R
-terpineol
unknown 3
MS, RI, Std
f
1.0
±
±
0.1
0.1
allyl benzoate
cinnamaldehyde
linalyl acetate
propyl benzoate
tridecane
isobutyl benzoate
eugenol
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
2.1
±
0.6*
0.3
17.9
±
±
0.1
1.7
0.6
0.2
0.1
±
±
0.5
0.1
0.2
2.1
0.6
0.3
±
0.1
R
-terpinyl acetate
neryl acetate
vanillin
0.6
0.5
0.5
0.8
±
±
±
±
0.1
0.1
0.1
0.1
MS, RI, Std
MS, RI, Std
MS, RI, Std
8.0
0.2
±
±
1.0
0.1
geranyl acetate
unknown 4
f
0.9
1.2
0.4
±
±
±
0.1
0.6
0.2
e
R
-copaene
-elemene
1.8
0.4
0.5
±
±
±
0.1
0.1
0.1
0.3
0.1
±
±
0.1
0.1
MS, RI
MS, RI
MS, RI
MS, RI, Std
MS, RI
MS, RI, Std
MS, RI
e
â
e
â-bourbonene
tetradecane
-
e
R
-gurjunene
-caryophyllene
0.3
1.5
0.3
â
±
±
0.1
0.1
0.4
±
0.2
e
â-gurjunene
0.1
±
0.1
f
unknown 5
0.3
±
0.1
0.7
0.3
±
±
0.1
0.1
e
γ
-muurolene
unknown 6
0.2
0.1
0.1
±
±
0.1
0.1
MS, RI
f
e
R
-selinene
valencene
MS, RI
MS, RI, Std
MS, RI
MS, RI
MS, RI
0.1
0.1
±
0.1
e
R
-muurolene
calamenenee
0.1
0.1
0.1
0.9
e
δ
-cadinene
benzyl benzoate
±
±
0.1
0.3
1.9
±
0.1
1.1
±
0.3
MS, RI, Std
a
b
Compounds are listed in order of their elution times from a HP1 column; compositional values lower than 0.1% are denoted as traces (tr). RI, retention indices,
c
d
determined on HP1 using the homologous series of n-alkanes. Reported percentages are relative; (%
±
SD) with SD
)
standard deviation. Method of identification: MS,
by comparison of the mass spectrum with those of the computer mass libraries; RI, by comparison of RI with those from the literature; Std, by injection of an authentic
e
sample. Compound tentatively identified according to the mass spectrum (MS) and by comparison of RI with the literature (RI): *, coelution, ratio corresponding to the
total integration of the two compounds; †, coelution with p-cymene. Unknown 1 (RI 1134): 134 (51.0), 119 (100), 105 (22.0), 91 (17.0), 77 (15.7). Unknown 2 (RI 1158):
f
136 (40.4), 122 (23.4), 121 (46.8), 119 (40.6), 111 (34.0), 93 (100), 91 (49.0), 77 (45.6), 71 (41.4), 43 (22.7). Unknown 3 (RI 1226): 162 (5.6), 106 (8.6), 105 (100), 77
(
27.2), 51 (7.3). Unknown 4 (RI 1365): 189 (100), 161 (44.5), 109 (39.2), 108 (25.9), 107 (23.9), 95 (27.7), 93 (33.1), 91 (27.0), 82 (42.1), 81 (24.0), 79 (22.8), 67 (24.5).
+
Unknown 5 (RI 1448): 204 (M , 22.0), 190 (16.0), 189 (100), 163 (15.4), 133 (24.7), 119 (15.4), 107 (12.3), 105 (15.3), 91 (18.5), 81 (11.7). Unknown 6 (RI 1478): 204
(
+
M , 80.0), 189 (67.0), 161 (80.2), 147 (52.0), 133 (57.7), 107 (80.2), 105 (100), 93 (83.3), 91 (67.8), 79 (58.1).

8852 J. Agric. Food Chem., Vol. 54, No. 23, 2006
Castel et al.
Table 2. Chemical Compositions of Volatile Extracts and Resinoids
volatile extracts
resinoids
R2 % SD
compounda
RIb
VE1 %
±
SDc
VE2 %
±
SD
R1 %
±
SD
±
SBR %
±
SD
identification methodsd
toluene
hexanal
furfural
750
772
800
845
853
871
872
874
882
933
0.1
0.3
tr
0.1
tr
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI
1-hexanol
0.1
tr
tr
tr
0.1
tr
± 0.1
e
p-xylene
heptan-2-one
styrene
heptanal
o-xylene
tr
0.1
benzaldehyde
9.6*
12.6
±
±
0.1*
0.1
R
-pinene
camphene
-heptanol
oct-1-en-3-ol
943
953
960
975
977
tr
1
0.1
0.2
tr
0.1
0.3
tr
0.1
0.1
0.1
0.3
0.1
0.2
0.1
0.9
0.1
tr
0.1
0.1
e
2-pentylfuran
octanal
â
-myrcene
978
997
R-phellandrene
benzyl alcohol
p-cymene
1009
1017
1019
1018
1022
1032
1033
1044
1054
1055
1076
1079
1082
1085
1089
1104
1110
1120
1129
1131
1141
1145
1158
1164
1168
1169
1180
1200
1211
1230
1240
1243
1247
1253
1261
1264
1273
1278
1286
1287
1298
1323
1326
1328
1336
1337
1350
1354
1368
1379
1385
1387
1407
1409
1412
1415
0.1
0.1
0.3
3.0
±
0.1
0.1
1,8-cineole
±
±
0.1
0.1
limonene
0.1
tr
(
(
Z)-
E)-
â-ocimene
e
â
-ocimene
oct-2(E)-enal
0.1
0.1
0.1
0.1
e
benzyl formate
-octanol
Z)-furanoid linalool oxide
1
± 0.1
e
e
(
(
0.4
0.3
0.1
15.4
0.4
4.4
tr
0.1
0.1
0.2
0.2
tr
E)-furanoid linalool oxide
±
0.1
MS, RI
terpinolene
methyl benzoate
nonanal
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI
17.3
0.3
1.5
±
0.1
±
±
±
0.4
0.1
0.2
tr
0.1 ± 0.1
linalool
R
1
-campholenic aldehydee
,2-dimethoxybenzene
camphor
benzyl acetate
non-2(E)-enal
p-ethylphenol
ethyl benzoate
tr
0.2
±
0.1
e
1.5
tr
0.1
0.8
0.2
0.2
0.7
±
±
0.1
3.6
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
1-nonanol
terpinen-4-ol
methyl salicylate
0.2
0.1
1.7
±
±
±
±
0.1
0.1
0.1
0.3
0.4
±
0.1*
R
-terpineol
decanal
0.1
MS, RI, Std
MS, RI, Std
benzoic acid
unknown 1
0.1
0.2
11.5
0.1
0.5
0.3
1.0
0.2
tr
42.6
±
3.2
28.6
±
1.1
41.7
f
allyl benzoate
dec-2(E)-enal
linalyl acetate
propyl benzoate
p-ethylguaiacol
nonanoic acid
thymol
undecan-2-one
p-vinylguaiacol
unknown 2
deca-2(E),4(E)-dienal
isobutyl benzoate
19.8
2.3
0.3
0.4
0.5
±
±
0.3
0.5
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI
±
0.1
tr
tr
tr
e
tr
0.1
e
MS, RI
f
5.2±
0.5
7.1
0.1
±
±
0.2
0.3
2.1
8.8
±
±
0.1
0.6
e
tr
0.1
MS, RI
0.2
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI
4
-hydroxybenzaldehyde
eugenol
-terpinyl acetate
0.1
1.2
0.1
1.3
R
neryl acetate
dihydroeugenol
vanillin
0.4
1.1
0.6*
0.1
0.2
0.1
tr
10.6
±
0.8
22.1
geranyl acetate
eugenol methyl ether
e
e
R
-copaene
-elemene
0.1
tr
tr
MS, RI
MS, RI
MS, RI
e
â
â
tr
e
-bourbonene
unknown 3
f
0.6
0.6
0.6
0.8
±
±
0.1
0.2
0.5
0.2
±
±
0.1
0.1
isoamyl benzoate
-methyl-3-butenyl benzoate
isoeugenol
0.1
0.4
0.1
0.3
MS, RI, Std
MS, RI, Std
MS, RI, Std
3
±
0.1

Chemical Composition of Siam Benzoin Gum Byproduct
J. Agric. Food Chem., Vol. 54, No. 23, 2006 8853
Table 2. (Continued)
volatile extracts
resinoids
compounda
RIb
VE1 %
tr
±
SDc
VE2 %
±
SD
R1 %
0.7
±
SD
0.1
R2 %
±
SD
SBR %
±
SD
identification methodsd
vanillyl ethyl ether†
1419
1421
1429
1437
1440
1453
1463
1482
1484
1488
1498
1502
1506
1520
1534
1540
1545
1551
1603
1608
1645
1662
1676
1685
1722
1730
1734
1827
1937
1979
2024
2216
2326
2423
2527
2563
±
1.1
±
0.1
0.3
±
0.1
MS
MS, RI, Std
MS, RI
â
-caryophyllene
e
â
-gurjunene
tr
acetovanillone
1.5
±
±
0.1
0.3
5.6
±
±
0.1
1.0
0.2
±
0.1
MS, RI, Std
f
unknown 4
0.5
0.5
0.1
tr
±
±
0.1
0.1
prenyl benzoate
0.3
MS, RI, Std
MS, RI
MS, RI
MS, RI, Std
MS, RI
MS, RI
e
benzyl tiglate
-selinene
e
â
2
R
R
0.1
±
0.1
-propiovanillone
4.1
1.3
0.5
4.7
0.1
1.2
1.0
0.7
±
±
0.5
0.1
e
-selinene
tr
tr
e
-muurolene
unknown 5
f
e
calamenene
tr
tr
MS, RI
MS, RI
e
δ
-cadinene
unknown 6
tr
f
e
hex-3(Z)-enyl benzoate
hexyl benzoate
0.1
tr
tr
tr
MS, RI
MS, RI, Std
MS, RI
MS
e
caryophyllene alcohol
†
homovanillic acid
1.6
0.1
±
0.1
1.2
0.2
f
unknown 7
1.2
±
0.1
e
cadalene
tr
MS, RI
MS, RI
MS, RI, Std
MS, RI, Std
MS, RI, Std
MS, RI, Std
e
methyl homovanillate
1.2
1.6
0.4
4.6
19.0
±
±
0.1
0.1
1.7
2.6
1.0
4.6
6.1
±
±
±
±
±
0.3
0.1
0.1
0.1
0.1
1.7
0.9
±
±
0.2
0.1
coniferaldehyde
coniferyl alcohol
benzyl benzoate
coniferyl ethyl ether
39.8
0.1
±
0.1
41.7
±
±
0.8
0.1
±
±
0.4
1.0
7.3
18.1
2.2
±
±
±
0.5
1.2
0.2
f
unknown 8
e
benzyl salicylate
0.2
0.2
MS, RI
MS, RI
e
palmitic acid
f
unknown 9
0.4
±
0.1
cinnamyl benzoate
0.1
MS, RI, Std
f
unknown 10
unknown 11
unknown 12
unknown 13
0.1
0.5
1.0
1.0
0.6
0.3
0.7
1.4
3.4
1.5
0.2
0.3
5.2
4.0
1.7
f
±
±
±
±
0.1
0.4
0.2
0.2
f
±
±
0.1
0.1
±
±
±
0.1
0.8
0.1
f
f
unknown 14
a
b
Compounds are listed in order of their elution times from a HP1 column; compositional values lower than 0.1% are denoted as traces (tr). RI, retention indices,
c
d
determined on HP1 using the homologous series of n-alkanes. Reported percentages are relative; (%
±
SD) with SD
)
standard deviation. Method of identification: MS,
by comparison of the mass spectrum with those of the computer mass libraries; RI, by comparison of RI with those from the literature; Std, by injection of an authentic
e
†
sample. Compound tentatively identified according to the mass spectrum (MS) and by comparison of RI with the literature (RI): , compound tentatively identified according
f
to the mass spectrum (MS); *, coelution, ratio corresponding to the total integration of the two compounds. Unknown 1 (RI 1211): 136 (22.8), 121 (30.1), 93 (100), 91
(37.7), 79 (28.1), 77 (25.2), 69 (97.1), 68 (43.5), 67 (38.1), 41 (66.8). Unknown 2 (RI 1286): 136 (2.1), 135 (2.6), 122 (3.8), 106 (8.0), 105 (100), 92 (3.0), 78 (3.8), 77
(
49.1), 51 (18.4), 50 (6.8). Unknown 3 (RI 1407): 166 (27.6), 138 (8.9), 137 (100), 122 (19.5), 94 (13.3), 77 (6.2), 66 (6.4), 65 (6.0), 51 (8.8), 39 (7.8). Unknown 4 (RI
+
1
1
4
2
1
440): 204 (M , 24.6), 190 (16.3), 189 (100), 163 (14.5), 133 (20.4), 107 (12.9), 105 (17.5), 91 (26.0), 79 (12.4), 41 (19.8). Unknown 5 (RI 1505): 208 (6.6), 163 (4.1),
06 (7.9), 105 (100), 77 (32.3), 51 (11.5), 50 (4.0). Unknown 6 (RI 1537): 194 (5.8), 152 (8.9), 151 (100), 123 (19.6), 108 (10.8), 105 (9.7), 77 (8.8), 65 (8.1), 52 (11.4),
3 (9.0). Unknown 7 (RI 1613): 178 (59.3), 149 (44.3), 134 (31.2), 133 (78.4), 131 (36.3), 121 (100), 103 (44.4), 91 (30.3), 77 (51.5), 55 (29.1). Unknown 8 (RI 1734):
24 (19.0), 150 (4.5), 138 (9.1), 137 (100), 122 (8.7), 94 (8.2), 66 (3.5), 65 (3.1), 59 (8.4), 51 (3.1). Unknown 9 (RI 1979): 296 (3.4), 182 (11.1), 181 (100), 153 (19.7),
31 (3.8), 125 (7.9), 103 (3.6), 93 (17.5), 65 (8.9), 59 (5.2). Unknown 10 (RI 2216): 281 (3.6), 250 (79.4), 165 (16.2), 152 (74.0), 151 (100), 137 (54.5), 135 (36.8), 79
(14.6), 55 (15.8), 39 (37.7). Unknown 11 (RI 2326): 286 (28.3), 164 (100), 149 (31.9), 137 (37.9), 133 (26.0), 132 (17.9), 105 (50.9), 91 (12.6), 77 (66.1), 51 (17.2).
Unknown 12 (RI 2423): 242 (0.3), 163 (7.5), 150 (25.7), 137 (92.0), 122 (11.5), 106 (8.4), 105 (100), 94 (12.0), 77 (36.6), 51 (12.8). Unknown 13 (RI 2527): 182 (11.0),
1
1
81 (100), 153 (16.3), 151 (5.0), 125 (6.7), 105 (19.9), 93 (20.0), 77 (16.3), 65 (9.0), 51 (4.5). Unknown 14 (RI 2563): 272 (2.6), 182 (9.2), 181 (100), 153 (17.9), 125 (6.4),
05 (18.4), 93 (20.0), 77 (15.0), 65 (9.0), 51 (4.6).
was isolated and characterized by GC-MS and H and 13C NMR.
Therefore, whereas (E)-coniferyl ethyl ether cannot be viewed
as natural, it is nevertheless characteristic of the extract. It should
be mentioned that this compound was previously described in
a Karo-Karunde flower absolute (20).
1
remaining resin to the byproduct resinoid (R1). Therefore, this
can be unambiguously related to its chemical composition,
which is close to that of SBR.
We decided to further investigate the overall composition of
the three resinoids by means of HPLC-UV analysis. The
chromatographic profiles obtained for the byproduct resinoid
(R1) and the SBR differed only by the absence of coniferyl
benzoate in the SBR. This compound is assumed to react more
easily with ethanol and water during the industrial manufacturing
process. In fact, a laboratory-made benzoin gum resinoid
produced under the same conditions as R1 showed an intense
coniferyl benzoate peak, thus displaying a very close similarity
to the byproduct resinoid after HPLC analysis. In contrast, the
chromatographic profile of the sorted byproduct resinoid (R2)
differed strongly from the two others, with the previously
The compositions established for the byproduct resinoids were
directly compared with those obtained for the commercial Siam
benzoin gum resinoid (SBR) (Table 2). According to the results
obtained, the byproduct resinoid (R1) appeared to be similar to
SBR. In contrast, the sorted byproduct resinoid (R2) was
different, mainly in that it had a lower content of benzoic acid
and coniferyl ethyl ether and a higher content of vanillic
derivatives, which were probably brought by the bark. In
addition, the difference between the yields obtained for R1
(
63%) and R2 (14%) clearly shows the contribution of the

8854 J. Agric. Food Chem., Vol. 54, No. 23, 2006
Castel et al.
observed major components nearly disappearing in R2. In view
of these results, we can conclude that the resinoids obtained
from grade 3 Siam benzoin gum and from the byproduct present
very similar chemical compositions.
The olfactory evaluation of the three resinoids was performed
by a perfumer using 10% ethanolic solutions. The byproduct
resinoid presented a weak vanilla top note and a benzoic acid
bottom note, providing a powdery, pungent, and balsamic effect.
The Siam benzoin gum resinoid afforded more pronounced and
persistent middle and bottom notes. In contrast, the sorted
byproduct resinoid provided a powerful vanilla, woody, and
sweety bottom note.
In conclusion, on the basis of these results showing a
similarity between extracts obtained from the byproduct and
Siam benzoin gum, this gum-harvesting byproduct could be
regarded as a new grade of Siam benzoin gum, possibly as a
grade 6. This grade, which contains a larger proportion of bark
than the other grades, presents interesting olfactory properties.
Finally, extracts obtained from this new grade could be
considered as new benzoin gum resinoids and may offer
attractive applications for the flavor and fragrance industry.
(8) Castel, C.; Fernandez, X.; Lizzani-Cuvelier, L.; Loiseau, A.-
M.; Perichet, C.; Delbecque, C.; Arnaudo, J.-F. Volatile con-
stituents of benzoin gums: Siam and Sumatra, part 2. Study of
headspace sampling methods. FlaVour Fragrance J. 2006, 21,
59-67.
(9) Davies, N. W. Gas chromatographic retention indices of monot-
erpenes and sesquiterpenes on methyl silicone and Carbowax
2
0M phases. J. Chromatogr. 1990, 503, 1-24.
(
10) (a) Joulain, D.; Konig, W. A. The Atlas of Spectral Data of
Sesquiterpene Hydrocarbons; E.B.-Verlag: Hamburg, Germany,
1
998; 658 pp. (b) Joulain, D.; K o¨ nig, W. A.; Hochmuth, D. H.
Terpenoids and related constituents of essential oils. Library of
Mass Finder 2.1, 2001.
(
11) McLafferty, F. W. The Wiley/NBS Registry of Mass Spectral
Data; Wiley: New York, 1989.
12) Adams, R. P., Ed. Identification of Essential Oil Components
by Gas Chromatography and Mass Spectroscopy; Allured
Publishing: Carol Stream, 1995.
13) Jennings, W.; Shibamoto, T. QualitatiVe Analysis of FlaVor and
Fragrance Volatiles by Glass Capillary Gas Chromatography;
Academic Press: New York, 1980; 472 pp.
(
(
(
14) Boelens Aroma Chemical Information Service, BACIS. ESO
2
000, The Complete Database of Essential Oils; Huizen, The
ACKNOWLEDGMENT
Netherlands, 1999.
We thank Laure Jacquet (CHARABOT S.A., Grasse, France)
for performing the olfactory evaluations. We also thank AGRO-
FOREX Co. for supplying the different benzoin raw materials.
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3
Received for review April 27, 2006. Revised Manuscript received
September 13, 2006. Accepted September 17, 2006. Contract/grant
sponsors: Conseil R e´ gional Provence Alpes C oˆ te d’Azur (ADER PACA)
and CHARABOT, Grasse, France.
JF061193Y