Volatile constituents of benzoin gums: Siam and Sumatra. Part 1

328 X. FERNANDEZ ET AL.

Copyright © 2003 John Wiley & Sons, Ltd. Flavour Fragr. J. 2003; 18: 328–333

FLAVOUR AND FRAGRANCE JOURNALFlavour Fragr. J. 2003; 18: 328–333Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/ffj.1230

Volatile constituents of benzoin gums: Siam andSumatra. Part 1

Xavier Fernandez,1 Louisette Lizzani-Cuvelier,1* André-Michel Loiseau,1 Christine Périchet2 and ClaireDelbecque2

1 Laboratoire Arômes, Synthèses, Interactions, Faculté des Sciences de Nice Sophia-Antipolis, Parc Valrose, 06108 Nice cedex 2,France

2 CHARABOT, Research Natural Products, 10 Av. Yves-Emmanuel Baudoin, 06130 Grasse, France

Received 14 February 2002

Revised 1 August 2002

Accepted 11 September 2002

ABSTRACT: The volatile extract composition of two different benzoin gums, Siam and Sumatra, were analysed

by GC–MS. Twenty components representing more than 99.1% of the oil from Siam and 29 components representing

more than 97.4% of the oil from Sumatra were analysed. The major components were benzyl benzoate (76.1–80.1%)

for the two oils and benzoic acid (12.5%), methyl benzoate (1.5%) and allyl benzoate (1.5%) for Siam, and styrene

(2.3%), cinnamic acid (3.5%) and benzyl cinnamate (3.3%) for Sumatra. Volatile compounds of oils and crushed

benzoins were also studied using solid-phase microextraction (SPME) employing carboxen/polydimethylsiloxane and

carbowax/divinylbenzene fibres. Copyright © 2003 John Wiley & Sons, Ltd.

KEY WORDS: benzoin gum Siam; benzoin gum Sumatra; balsam; GC–MS; benzyl benzoate; benzoic and cin-

namic acids; solid phase microextraction (SPME)

* Correspondence to: L. Lizzani-Cuvelier, Laboratoire Arômes, Synthèses,

Interactions, Faculté des Sciences de Nice Sophia-Antipolis, Parc Valrose,

06108 Nice cedex 2.

E-mail: [email protected]

Introduction

Benzoin gum is a balsam obtained from trees of the

Family Styracaceae. It is produced mainly in Asia from

places such as Indonesia, Sumatra, Java, Laos, Thailand

and Vietnam. Two types of benzoin gum exist in the

trade: benzoin gum Siam from Styrax tonkinensis Craib

and benzoin gum Sumatra from Styrax benzoin Dryan-

der.1 Under normal conditions, the tree does not produce

any resin; it is a pathological product that is only pro-

duced after deep incisions are made in the bark.

Benzoin gum Siam is externally reddish yellow and

internally milky white. Its odour is pleasant, sweet-

balsamic with a distinct note of vanilla. Siam is particu-

larly useful in brown flavours, such as vanilla, chocolate,

nuts.2 This resin is graded according to the size of the

pieces. They occur in the trade in four different grades:

1 (very large tears, without any foreign particles) to 4

(very small, powder-like). Sumatra comes in pieces that

are reddish to greyish-brown in colour. Fine qualities

present a strong styrax-like odour, quite distinct from the

vanilla odour of the Siam variety. It is often used in soap

and detergent fragrances for this reason as well as its

fixative properties. Its robust character is normally pre-

ferred to flavour tobacco products.2 Sumatra is also fre-

quently sold under four grades called A, B, C and D by

some collectors and under only two or three grades by

others.

Even if these resins are widely used in flavour and fra-

grance, there have been only a few studies on the chemi-

cal composition of Siam or Sumatra benzoin gums. In

1914, Reinitzed found that the major constituent of Siam

is coniferyl benzoate 75–80%.3 Schroeder’s work shows

that Siam is composed of coniferyl benzoate (65–75%),

p-coumaryl benzoate (10–15%), cinnamyl cinnamate

(0.5–6%), benzoic acid (12%), vanilline (0.3%) and

siaresinolic acid (6%).4 Sumatra is reported to contain

more cinnamic acid and cinnamates than Siam.5 One

study presented a comparative analysis of volatile com-

pounds of Siam and Sumatra.2 In this study, 17 com-

pounds are described in the volatile fraction of Siam, the

major products are benzyl alcohol (38.8%), benzoic acid

(18.4%) and benzyl benzoate (39.3%). For Sumatra, 15

compounds are presented, with benzyl alcohol (43.4%)

and benzyl benzoate (50.7%) as the major constituents.

However, the experimental procedure to obtain the vola-

tile fractions is not described. One other study presented

volatile compounds in Sumatra but experimental proce-

dure and compounds ratio are not mentioned.6

In the present work we studied the chemical com-

position of the volatile extracts obtained from Siam and

Sumatra benzoin gums by direct GC injection of the oils.

VOLATILE CONSTITUENTS OF SIAM AND SUMATRA BENZOIN GUMS 329


Volatile compounds of oils and crushed benzoin gums

were also studied by SPME.

Experimental

Material

Benzoin gum Siam (from Styrax tonkinensis Craib) was

collected in north Laos and graded as Benzoin Gum Siam

Grade 3, and was purchased in early 2001; Sumatra

(from Styrax benzoin Dryander) was collected in Indone-

sia and graded as Benzoin Gum Sumatra Grade B and

was purchased in early 2001.

Isolation of Volatile Extracts

Siam and Sumatra benzoin gums (50 kg) were submitted

to hydrodistillation in a 1000 l apparatus for 11 h using

n-hexane (5 l) as a recovery solvent for the oil. Volatile

oils were obtained in 0.14% yield (52 g) for Siam and

0.07% yield (27 g) for Sumatra.

GC–MS

The oil was analysed by GC–MS using a Hewlett-

Packard 5890/5970A system, with a HP1 column (50 m

× 0.20 mm, film thickness, 0.5 µm). GC oven initial tem-

perature was 60 °C and programmed to 220 °C at a rate

of 2 °C/min and then head at 220 °C for 45 min under

the following operation conditions: carrier gas, helium;

injector and detector temperatures, 250 °C; injected

volume, 0.4 µl (20% hexane solution); split ratio, 1:80.

Retention indices were determined with C5–C28 alkane

standards as reference. The mass spectra were performed

at 70 eV, mass range 35–400. Identification of the con-

stituents was based on comparison of the retention times

with those of pure references and on computer matching

against a commercial library (Wiley, MassFinder 2.1

Library) and a home made mass spectra library built up

from pure substances and MS literature data.7–11

SPME Procedure

A manual SPME device and fibres were obtained from

Supelco (PA, USA). Two different fibres were used:

carboxen/polydimethylsiloxane CAR/PDMS StableFlex

(75 µm; Supelco, Catalogue No. 57334-u) and carbowax/

divinylbenzene CW/DVB (65 µm; Supelco, Catalogue

No. 57312). Before use, the fibres were conditioned as

recommended by the manufacturer. The fibre was ex-

posed to the headspace of crushed benzoin gum (10 g, 30

min) or volatile extracts (3 g, 2 min) in a 40 ml amber

vial closed by a PTFE/silicone septum (Supelco, Cata-

logue No. 27121-u). The containers were allowed to

stand overnight before any SPME sampling of the head-

space occurred. After exposure, the fibre was injected

into the gas chromatograph and left in the injection port

(equipped with a 0.75 mm i.d. inlet liner) for 4 min. The

injector temperature was set at 250 °C and operated in

the splitless mode for 4 min unless otherwise stated.

After 4 min at 60 °C, the temperature was increased at a

rate of 2 °C min to 230 °C and then heated at 230 °C for

45 min. Before sampling, each fibre was reconditioned

for 15 min in the GC injection port at 230 °C.

HS–GC

Benzoin gums were analysed by HS–GC to determine

the toluene and styrene titrations: a Hewlett-Packard

7694/6850 system equipped with a BP-1 column (30 m

× 0.25 mm, 0.25 µm film thickness) was used. The

headspace injector was static, with a working temperature

of 70 °C and a stabilization time of 30 min. GC oven

initial temperature was maintained at 35 °C for 10 min

then increased from 35 °C to 220 at a rate of 10 °C/min.

Injector and detector temperature were 250 °C; carrier

gas, helium; split ratio, 1/10. The toluene and styrene

titrations were calculated by external calibration. Studies

were realized with 2 g crushed benzoin gums. HS vials

were allowed to stand overnight before any analysis.

Results and discussion

The components of the essential oils, the percentages of

the constituents (by direct integration) and the retention

indices are listed in Table 1. Chromatographic profiles of

the volatile extracts revealed 20 identified constituents,

which represented 99.1% of the total GC–MS area for

Siam and 29 identified constituents which represented

97.4% of the total GC–MS area for Sumatra. The analy-

sis revealed that Siam oil contained one aromatic car-

boxylic acid (benzoic acid, 12.5%), eight esters (84.8%),

seven sesquiterpene hydrocarbons (0.4%). For the

Sumatra species, we observed two aromatic carboxylic

acid (benzoic and cinnamic acids, 5.2%), 10 esters

(82.7%) and six sesquiterpene hydrocarbons (2.4%). The

major components are benzyl benzoate (76.1–80.1%) for

the two oils and benzoic acid (12.5%), methyl benzoate

(1.5%) and allyl benzoate (1.5%) for Siam, and styrene

(2.3%), cinnamic acid (3.5%) and benzyl cinnamate

(3.3%) for Sumatra.

Compounds present in oils were also studied by solid-

phase microextraction (SPME). This technique is based

on the differential sorption of compounds to a fused-silica

fibre coated with a polymeric organic liquid phase.12 Con-

siderable research has been done on the application of



Table 1. Chemical composition of the volatile extracts of Siam and Sumatra benzoin gums

Compoundsa RI Siam benzoin Sumatra benzoin

Styrene* 876 – 2.3

Benzaldehyde* 932 0.4 0.9

6-Methyl-5-hepten-2-one 962 – tr

Phenyl acetaldehyde 1011 – tr

1,8-Cineole* 1025 0.1 0.4

Acetophenone* 1037 – 1.8

Methyl benzoate* 1071 1.5 0.5

Benzoic acid* 1138 12.5 1.7

Ethyl benzoate* 1147 1.1 0.2

Allyl benzoate* 1232 1.5 0.9

(E)-Cinnamaldehyde* 1235 – 0.7

Propyl benzoate* 1247 0.2 0.1

4-Ethylguaiacol 1254 0.1 0.6

Isobutyl benzoate* 1306 tr –

Eugenol* 1331 1.1 0.8

Dihydroeugenol* 1344 tr tr

α-Copaene 1385 tr tr

β-Elemene 1394 tr –

Cinnamic acid* 1396 – 3.5

Isoamyl benzoate* 1415 0.1 –

trans-α-Bergamotene 1417 – 0.2

3-Methylbut-3-enyl benzoate* 1422 0.3 –

β-Caryophyllene* 1430 tr –

Ethyl cinnamate* 1436 – 0.1

Unknownb 1470 0.3 2.2

Valencene 1483 tr tr

Ledene 1493 tr tr

∆-Guaiene 1502 0.1 tr

Allyl cinnamate* 1524 – 0.5

(E)-Nerolidol 1550 – 0.4

Isobutyl cinammate* 1601 – 0.1

Benzyl benzoate* 1742 80.1 76.1

Cinnamyl benzoate* 2033 – 1.4

Benzyl cinnamate* 2048 – 3.3

(E)-Cinnamyl-(E)-Cinnamate* 2344 – 0.9

a Compounds are listed in order of their elution from a HP1 column.b Unknown: 204(M+, 22.1), 189(100), 147(12.1), 134(11.3), 119(14.1), 107(16.3), 105(26.5), 93(14.9), 91(22.7), 79(12.1), 77(12.4), 55(9.8), 41(12.9).

RI, retention indices as determined on HP1 using the homologous series of n-alkanes; tr, trace (< 0.1%).

* Structure confirmed by standard compound injection.

this technique for volatile flavour analysis.13–15 Several

fibres are available in accordance with compounds to

studied and Bicchi’s works show that the most effective

fibres for head-space-SPME are those consisting of two

components, a liquid (PDMS) for the less polar compo-

nents and a solid (DVB or CAR) polymer coating for the

more polar compounds.16

In this work, we have selected two fibres: carboxen/

polydimethylsiloxane (CAR/PDMS) and carbowax/divinyl-

benzene (CW/DVB). CAR/PDMS fibre is recommended

for low molecular weight compounds17 and has been

described as the best fibre to characterize volatile com-

pounds such as menthol.18 The mixed coating CW/

DVB was tried, as it was considered suitable for the

analysis of polar semivolatiles.19 Compounds present

in oil with these two fibres are listed in Table 2. Due

to fibre selectivity and the low volatility of benzyl

benzoate, SPME studies lead to the identification of

new compounds in oil such as ethanol, toluene, α- and

β-pinene, linalool oxide, terpinen-4-ol, α-ylangene and

other sesquiterpene hydrocarbons. On the other hand,

SPME analyses are not able to identify low volatile

compounds such as benzyl cinnamate, cinnamyl benzoate

or cinnamyl cinnamate. The ratios obtained are not sig-

nificant and are dependent only on compound affinities

with the fibre.

Compounds found here in benzoin volatile extracts

from Laos and Indonesia are in good agreement with

those found in the previously published work for aro-

matic esters and acids.2 However, we do not observe the

presence of benzyl alcohol, nevertheless described as

very abundant in Moyler’s works.2 This observation can

be explained by the procedure used to obtained the vola-

tile fractions. We also observe that volatile fractions

obtained do not contain vanillin, which has nevertheless

been described as present at trace level among the vola-

tile compounds of Siam and Sumatra benzoin gums.2,6

To check the presence of benzyl alcohol and vanillin

in benzoin gums, we performed SPME analyses on

crushed Siam and Sumatra benzoin gums with CAR/



Table 2. SPME studies of Siam and Sumatra benzoin volatile extracts

Compoundsa Siam benzoin Sumatra benzoin

Fibre Ab Fibre Bc Fibre A Fibre B

Ethanol 4.5 4.2 2.7 3.1

Toluene 13.5 1.2 tr –

Styrene 2.5 0.5 61.3 51.0

Benzaldehyde 13.6 28.2 13.2 16.5

α-Pinene 19.1 – – –

6-Methyl-5-hepten-2-one – 0.3 0.7 0.9

β-Pinene 1.4 0.4 – –

Trimethylbenzene 0.3 0.3 – –

Phenyl acetaldehyde – – 0.1 0.3

α-Phellandrene 0.2 – – –

Isoterpinolene – 0.1 – –

p-Cymene 2.2 1.0 0.2 0.2

1,8-Cineole 15.0 5.8 6.1 4.3

Benzylformate – 0.1 – –

Acetophenone 0.2 tr 6.2 11.2

γ-Terpinene 0.1 0.2 – –

Linalool oxide 1.8 1.0 0.1 tr

Methyl benzoate 16.0 33.7 3.5 3.6

Linalool – 0.3 – –

Benzoic acid 1.3 0.9 0.2 tr

Ethyl benzoate 1.4 5.3 0.6 0.7

Terpinen-4-ol tr 0.1 0.1 0.1

Allyl benzoate 0.7 5.7 0.4 1.1

(E)-Cinnamaldehyde – – – 0.3

Propyl benzoate – 1.0 0.1 0.2

4-Ethylguaiacol – 0.2 0.1 0.4

Isobutyl benzoate – 0.1 – tr

Eugenol tr 0.6 tr 0.2

∆-Elemene 0.9 0.5 0.3 0.2

α-Ylangene 1.0 0.1 tr tr

α-Copaene 1.6 0.9 0.4 0.3

β-Elemene 0.7 0.5 0.2 0.1

trans-α-Bergamotene – – 0.3 0.3

β-Caryophyllene 0.6 0.4 0.1 0.2

Unknownd 1.1 0.7 2.5 2.7

Germacrene D – 0.3 – –

Valencene 0.1 tr tr tr

α-Muurolene tr 0.3 – –

Ledene 0.2 0.3 tr 0.1

∆-Guaiene – 0.1 – –

∆-Cadinene tr 0.1 tr 0.1

Benzyl benzoate – 1.6 – 0.3

a Compounds are listed in order of their elution from a HP1 column.b Carboxen/polydimethylsiloxane fibre (75 µm).c Carbowax/divinylbenzene fibre (65 µm).d See Table 1.

tr, trace (< 0.1%).

PDMS and CW/DVB fibres. Several sorption times were

tested (10, 15, 30 and 45 min) and the best results were

obtained with a time of 30 min. Compounds present in

the headspace of Siam and Sumatra crushed benzoin

gums are listed in Table 3. SPME analyses to crushed

Siam and Sumatra benzoin gum were able to identify

new volatile constituents in analogy of essential oil such

as benzyl alcohol, vanillin, acetic and propanoic acid,

ethylbenzene and phenol.

Studies of head space with CAR/PDMS fibre gum

lead to the identification of a large quantity of toluene

(> 65%) in Siam benzoin and styrene (> 90%) in Sumatra

benzoin, in all our analyses. To determine the real quan-

tities of these compounds in benzoin gums, we performed

static HS–GC titrations of these compounds. We found a

quantity of 10 ppm toluene in Siam benzoin and trace

level (< 1 ppm) in Sumatra benzoin. We found a quan-

tity of 800 ppm styrene in Sumatra benzoin and a trace

level in Siam benzoin. These results show that these large

quantities observed for toluene in Siam benzoin and

styrene in Sumatra benzoin was due to the high affinity

of these compounds with the CAR/PDMS fibre in oper-

ating conditions. The CAR/PDMS fibre represents a very

useful fibre for the detection of non polar hydrocarbon

compounds, but it is not recommended for qualitative

study of benzoin gums.



Table 3. SPME studies of crushed Siam and Sumatra benzoin gums

Compoundsa Siam benzoin Sumatra benzoin

Fibre Ab Fibre Bc Fibre A Fibre B

Ethanol 0.2 1.5 0.4 0.7

Acetic acid 4.1 1.1 0.8 0.9

3-Buten-2-ol 0.6 – – –

Propanoic acid 0.4 0.1 – –

Toluene 66.4 1.2 0.3 –

Ethylbenzene 0.2 – – –

Styrene 5.0 – 90.4 70.1

Benzaldehyde 4.4 5.9 1.3 3.2

α-Pinene 4.5 – 0.2 –

Phenol – – 0.7 2.3

6-Methyl-5-hepten-2-one – – – tr

Phenyl acetaldehyde – – – 0.1

Isoterpinolene – 0.1 – –

Benzyl alcohol 2.4 11.2 – 0.4

p-Cymene 0.4 0.3 0.3 0.3

1,8-Cineole 0.6 – 0.3 0.4

Acetophenone 0.4 – 1.5 7.6

Benzylformate 0.2 0.8 – –

Linalool oxide tr 0.3 – tr

Methyl benzoate 2.0 8.7 0.3 tr

Benzoic acid 4.8 43.4 0.6 3.9

Ethyl benzoate 1.4 12.1 – 1.3

Allyl benzoate – tr – tr

(E)-Cinnamaldehyde – – – 1.0

Propyl benzoate – 0.5 – 0.2

4-Ethylguaiacol – 0.5 – 0.1

Isobutyl benzoate – 0.7 – tr

Eugenol – 1.6 – 0.2

∆-Elemene 0.5 – – –

Vanillin 0.1 3.2 – 0.4

α-Copaene 0.1 – – –

β-Caryophyllene 0.3 – – –

Unknownd 1.7 0.7 2.3 7.5

Germacrene D – 0.1 – –

Benzyl benzoate – 4.1 – 0.3

a Compounds are listed in order of their elution from a HP1 column.b Carboxen/polydimethylsiloxane fibre (75 µm).c Carbowax/divinylbenzene fibre (65 µm).d See Table 1.

tr, trace (< 0.1%).

Conclusions

In conclusion, our GC–MS studies of Siam and Sumatra

volatile extracts led to the identification of 20 and 29

compounds, representing 99.3% and 97.2% of the total

area. The major components were benzyl benzoate (76.1–

80.1%) for the two oils and benzoic acid (12.5%), methyl

benzoate (1.5%) and allyl benzoate (1.5%) for Siam,

styrene (2.3%), cinnamic acid (3.5%) and benzyl

cinnamate (3.3%) for Sumatra.

The headspace analyses by SPME of oils and crushed

benzoin gums were able to identify new compounds, in

particular benzyl alcohol and vanillin, which were iden-

tified in crushed Siam and Sumatra but not in the oils.

This technique seems particularly adequate to the studies

of balsams and SPME analyses of volatile constituents of

different qualities of Siam and Sumatra benzoin gums are

under current study, using different fibres (PDMS, CW/

DVB and polyacrylate).

The direct and SPME analyses of Siam and Sumatra

benzoin volatile extracts show the presence of ses-

quiterpene hydrocarbons at trace level. The fractionation

of these oils, GC and GC–MS studies of the different

fractions obtained, will be the subject of a further

publication.

References

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Volatile constituents of benzoin gums: Siam and Sumatra. Part 1

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