Volatile Flavor Constituents of Fruits from Southern Africa: Mobola Plum (Parinari curatellifolia)

Article abstract of DOI:10.1021/jf030702i

The volatile flavor components of Mobola plum (Parinari curatellifolia), a native fruit of Southern Africa, have been isolated by a vacuum headspace concentration method. The concentrate was analyzed by hyphenated gas chromatographic techniques, including gas chromatography (GC)/mass spectrometry (MS) and GC/Fourier transform infrared (FTIR), together with other GC-coupled detection devices for the specific and selective detection of nitrogen- and sulfur-containing compounds. A total of 88 components were identified. Of these compounds, 12 contain nitrogen, including 2-aminobenzaldehyde and phenylacetaldoxime, which are detected for the first time in an edible fruit. In addition, two unusual nitrated compounds have been identified, including optically active (2-nitrobutyl)benzene, which is a new natural product. Quantitative and sensory data of the new compounds are provided.

Full text of DOI:10.1021/jf030702i

2322 J. Agric. Food Chem. 2004, 52, 2322−2325
Volatile Flavor Constituents of Fruits from Southern Africa:
Mobola Plum (Parinari curatellifolia)
DANIEL JOULAIN,*,† ANDREÄ CASAZZA,† RAYMOND LAURENT,† DAVID PORTIER,†
§
NADINE GUILLAMON,† RAJESH PANDYA,‡ MING LE,‡ AND ALVARO VILJOEN
Research Division, Robertet S.A., BP 52100, F-06131 Grasse Cedex, France, Robertet Flavors, Inc.,
10 Colonial Drive, Piscataway, New Jersey 08854, and Department of Pharmacy,
University of Witwatersrand, 7 York Road, Parktown, 2193, South Africa
The volatile flavor components of Mobola plum (Parinari curatellifolia), a native fruit of Southern Africa,
have been isolated by a vacuum headspace concentration method. The concentrate was analyzed
by hyphenated gas chromatographic techniques, including gas chromatography (GC)/mass spec-
trometry (MS) and GC/Fourier transform infrared (FTIR), together with other GC-coupled detection
devices for the specific and selective detection of nitrogen- and sulfur-containing compounds. A total
of 88 components were identified. Of these compounds, 12 contain nitrogen, including 2-aminoben-
zaldehyde and phenylacetaldoxime, which are detected for the first time in an edible fruit. In addition,
two unusual nitrated compounds have been identified, including optically active (2-nitrobutyl)benzene,
which is a new natural product. Quantitative and sensory data of the new compounds are provided.
KEYWORDS: Mobola plum flavor; Parinari; chrysobalanaceae; vacuum headspace method; GC/MS; nitro
compounds
INTRODUCTION
Sample Preparation. The method similar to vacuum headspace (2)
was used with some modifications. It involved a 4 L round bottom
flask fitted with a mechanical stirrer. The aqueous distillate was
precooled in a descending condenser with circulating water at 4° C,
before being condensed in two successive cooling traps (dry ice-
acetone). A total of 2576 g of fruit pulp (pH 6.2) was placed in the
flask with 257 µL of a 0.1% solution (w/vol) of veratrole (internal
standard, 0.1 ppm), in analytical grade methylene dichloride (CH2Cl2).
Subsequently, a vacuum was applied during 5 h (5-10 mbar) so that
the internal temperature was constantly maintained at 20-23 °C. At
the end of the sampling period, the aqueous distillates were pooled
(ca. 500 g) and extracted with pentane/CH2Cl2 (51/49, w/w), and the
solvent was evaporated to a final volume of ca. 50 µL.
Quantitation. The quantitative results shown in Table 1 were
determined based on the response factors of all ingredients being equal
to 1 for the total extraction procedure, except in the case of 2-phen-
ylethanol, since its content is far outside the concentration range of all
of the other constituents. Its approximate concentration was determined
by carrying out a model liquid/liquid extraction of a known amount of
analyte with the same solvent system. The recovery rate of selected
nitrogen-containing compounds during the total isolation process was
determined by carrying out model experiments; phenylacetonitrile
(1.05 mg), 2-aminobenzaldehyde (0.232 mg), phenylacetaldoxime
(0.752 mg), (2-nitroethyl)benzene (1.0 mg), and (2-nitrobutyl)benzene
(0.942 mg) in 2.5 L of water at pH 6.2 were submitted to vacuum
hydrodistillation for 2 h. Then, 0.670 mg of veratrole was added to the
aqueous distillate (ca. 440 g) prior to extraction and workup as above.
In a separate experiment, similar amounts of the five compounds were
added in water (300 mL) containing a known amount of veratrole, and
extraction was carried out as above. Recovery rates were calculated
in taking into account the GC/FID response factors of the five
analytes.
The Mobola plum tree, Parinari curatellifolia Planchon ex
Benth. (Chrysobalanaceae) is a large evergreen tree, which
grows up to 13 m high. It is distributed along the eastern coast
of South Africa and extends into the Limpopo Province. It is
also found in the southern parts of Zimbabwe and is reported
to grow in parts of Mozambique and Malawi. The oval (50 mm
× 25 mm), russet-yellow, pitted fruits have a yellow flesh with
a pleasant taste. Wild Mobola plum, or sand apple, is consumed
by local people, who eat it fresh or prepared as a syrup (1). In
many parts of Southern Africa, a beer is brewed from this fruit.
Because the flavor of Mobola plum has not been studied so
far, we report herein the study of the volatile fraction, using a
sampling procedure of proven efficacy and a combination of
hyphenated gas chromatographic techniques for the identification
of individual components: gas chromatography/mass spectrom-
etry (GC/MS), gas chromatography with Fourier transform
infrared (GC/FTIR) detection, gas chromatography with pulsed
flame photometric detection (GC/PFPD), and gas chromatog-
raphy with nitrogen chemiluminescence detection (GC/NCD).
MATERIALS AND METHODS
Materials. Fresh ripe fruits were collected in October 2002 from
wild-growing trees near Thohoyandu (Venda), South Africa.
* To whom correspondence should be addressed. Tel: +33 4 93403366.
Fax: +33 4 93706809. E-mail: daniel.joulain@robertet.fr.
† Robertet S.A..
‡ Robertet Flavors, Inc..
§ University of Witwatersrand.
10.1021/jf030702i CCC: $27.50 © 2004 American Chemical Society
Published on Web 03/27/2004

Volatiles in Mobola Plum
J. Agric. Food Chem., Vol. 52, No. 8, 2004 2323
Table 1. Volatile Compounds Identified in Parinari Fruit Flavor
a
a
compound
RI
Cb
47
17
43
26
tr
110
292
1148
1407
88
58
433
tr
tr
tr
24
tr
tr
53
13
tr
compound
isobutyl butyrate
butyl acetate
butyl propionate
RI
Cb
esters
methyl butyrate
315
411
423
523
688
200
300
400
500
448
538
600
800
1000
1200
427
539
630
760
836
1005
1168
310
413
445
548
553
860
1127
554
412
507
595
648
650
693
793
962
tr
73
methyl isovalerate
methyl pentanoate
methyl hexanoate
methyl benzoate
130
403
tr
59
127
tr
butyl butyrate
butyl 2-methylbutyrate
butyl 3-methylbutyrate
butyl pentanoate
butyl hexanoate
butyl benzoate
ethyl acetate
ethyl propionate
ethyl butyrate
ethyl pentanoate
ethyl 2-methylbutyrate
ethyl 2-methylpentanoatee
ethyl hexanoate
ethyl octanoate
ethyl decanoate
ethyl dodecanoate
ethyl crotonate
ethyl (E)-2-methyl-2-butenoate
ethyl 2-methyl-2-pentenoate
ethyl benzoate
ethyl phenylacetate
ethyl anthranilate
diethyl phthalatec
propyl acetate
propyl propionate
propyl isobutyrate
propyl 2-methylbutyrate
propyl 3-methylbutyrate
propyl benzoate
tr
tr
tr
butyl anthranilate
1213
474
571
3-methylbutyl acetate
3-methylbutyl propionate
3-methylbutyl butyrate
3-methylbutyl anthranilate d
benzyl benzoate
phenylethyl acetate
phenylethyl propionate
phenylethyl butyrate
phenylethyl isobutyrate
phenylethyl 2-methylbutyrate
phenylethyl 3-methylbutyrate
phenylethyl pentanoate
phenylethyl (E)-2-methyl-2-butenoate
phenylethyl 4-methylpentanoate
phenylethyl hexanoate
phenylethyl benzoate
phenylethyl phenylacetate
3-(acetyloxy)-2-butanone
3-(butanoyloxy)-2-butanone
112
128
tr
10
80
174
987
11
tr
660
1277
1350
848
945
1031
996
1098
1100
1140
1178
1165
1233
1445
1508
474
790
135
tr
tr
38
74
114
21
115
17
tr
10
tr
28
tr
35
tr
propyl anthranilate
658
alcohols
1-butanol
3-methyl-1-butanol
1-hexanol
238
319
466
446
180
77
55
tr
1-octen-3-ol
R-terpineol
2-phenylethanol
583
793
700
17
32
=12 600
(Z)-3-hexenol
phenols
2-methoxy-4-methylphenol (creosol)
eugenol
781
949
tr
30
vanillin
983
tr
carbonyls
1-phenyl-2-butanone
(E)-2-hexenal
benzaldehyde
phenylacetaldehyde
436
543
630
tr
tr
tr
816
1217
1344
tr
tr
tr
benzophenone
dibenzyl ketone
miscellaneous N and S compounds
benzyl cyanide
719
866
999
848
865
798
620
460
67
quinoline
benzothiazole
methyl 3-(methylthio)propionate
ethyl 2-(methylthio)acetatef
ethyl 3-(methylthio)propionate
propyl 3-(methylthio)propionate
817
802
612
573
689
788
tr
tr
17
tr
tr
tr
(2-nitroethyl)benzene
(2-nitrobutyl)benzene
syn-phenylacetaldoxime
anti-phenylacetaldoxime
2-aminobenzaldehyde
54
18
a Retention indices calculated relative to ethyl esters of normal chain aliphatic acids (4). b Approximate concentrations in µg/kg of fresh fruit; concentrations below 10
µg/kg are noted as tr (trace). c Analytical artifact. d Tentative identification: MS [m/z (%)]: 65 (33), 92 (42), 119 (100), 120 (46), 137 (51), 207 (34). e MS [m/z (%)]: 43
f
(75), 55 (13), 71 (55), 74 (52), 87 (12), 99 (28), 102 (100), 115 (12), 129 (1), 144 (<1). Identified by GC/PFPD only.
GC/FTIR Spectroscopy. For GC/FTIR analyses, an IRD II (Bio-
Rad, Cambridge, MA) equipped with a liquid nitrogen-cooled wide-
band MCT detector (4000-750 cm-1) and coupled to an Agilent 6890
gas chromatograph (Agilent, Palo Alto, CA) was used. The gas
chromatograph was equipped with a CP-Sil 5CB column, 50 m × 0.32
mm ID, df ) 0.4 µm (Varian, Les Ulis, France) and operated in splitless
mode (injected volume, 1 µL); the injector temperature was 250 °C;
the constant flow rate of the helium was 1 mL/min. The oven
temperature program was 60-280 °C at 2 °C/min and was held at 280
°C for 35 min. The end of the column was connected to the inlet of
the light pipe (120 mm × 1 mm), heated at 280 °C using a transfer
line heated at 290 °C. Makeup gas (nitrogen, 5 psi) was added to both
GC/FTIR interfaces to maintain chromatographic resolution. Gram-
Schmidt chromatograms were processed with Grams/32 IRD software
(Galactic, Salem, MA).
× 0.32 mm ID, df ) 0.4 µm (Varian), and coupled to a 5972 quadrupole
mass selective detector (Hewlett-Packard). The column was operated
at 1 mL/min helium constant flow; the temperatures of the injector
and transfer line were 250 and 280 °C, respectively. The oven
temperature program was 65 °C isothermal for 10 min, raised at 5°/
min to 280 °C, and then isothermal at 280 °C for 30 min.
Chirospecific GC. The chiral separation was carried out at 110 °C
(isothermal) with a custom-made capillary column (10 m × 0.25 mm,
df ) 0.25 µm) coated with 2,3-diacetoxy-6-tbutyldimethylsilyl-â-
cyclodextrin at 50% in OV 1701.
Analysis of Sulfur-Containing Compounds. Selective detection of
sulfur compounds was carried out with an Agilent 5890A gas
chromatograph, equipped with a split/splitless injector (injected volume,
1 µL in splitless mode), and the injector temperature was 250 °C.
Separations were performed using the same type of column and flow
rate as for the GC/MS experiments. The oven temperature program
was 60-280 °C at 2°/min and was held at 280 °C for 20 min. At the
GC/MS. A Hewlett-Packard (Palo Alto, CA) 5890 series II gas
chromatograph was used, equipped with a CP-Sil 5CB column, 50 m

2324 J. Agric. Food Chem., Vol. 52, No. 8, 2004
Joulain et al.
end of the capillary column, a silica Y-splitter was used to send 20%
of the flow to a flame ionization detector (temperature, 280 °C) and
80% of the flow to a model 5380 pulsed flame photometric detector
(OI Analytical, College Station, TX). The detector temperature was
250 °C; the voltage was 600 V; the sulfur gate was 6-24.9 ms; and
the detector trigger was 800 mV. The gas flows to the detector were
11.5 mL/min of H2, 12 mL/min air-2, and 10 mL/min air-1. The
signals were processed with HP ChemStation software, and sulfur
compounds were identified by their Kovats indices calculated with
respect to linear methyl thioesters, which have been shown to be well-
correlated with those of normal chain ethyl esters (3), and comparison
with an in-house database.
Nitrogen-Containing Compounds Analysis. Nitrogen-containing
compounds were analyzed with a chemiluminescence nitrogen detector
(7090 Series from Antek, Houston, TX), fitted to an Agilent 6890 gas
chromatograph). The nitrogen detector was fed with H2 (250 mL/min)
and O2 (5 mL/min). The chromatograph was fitted with a DB-1 column,
10 m × 0.18 mm ID, df ) 0.4 µm (Agilent). The column was operated
at 1.5 mL/min helium constant flow, and the temperature of the injector
was 250 °C. The oven temperature program was 40 °C isothermal for
1 min, then raised at 40 °C/min to 260 °C, and held at that temperature
for 0.5 min. To allow further confirmation of identifications, the system
was coupled in parallel with a Pegasus time-of-flight mass spectrometer
(Leco, St. Joseph, MI), operating with a 50 spectra/s acquisition rate
(35-355 amu).
Figure 1. Structures of 2-aminobenzaldehyde (1), phenylacetaldoxime
(2), (2-nitroethyl)benzene (3), and (2-nitrobutyl)benzene (4).
flavor, which otherwise is dominated by the typical fruity note
provided by various ethyl esters, which themselves represent
the major part within the ester category. Among these, ethyl
2-methylpentanoate is unusual in a fruit flavor: as of today, it
has been reported only in the volatile fraction of durian (10).
However, it is a product of commerce in the fragrance industry
with an odor described as “a high impact fresh, fruity-green
note, evocative of ripe apple skin” (Manzanate, a trade name
of Quest International). While (3-acetyloxy)-2-butanone (so-
called acetoin acetate) has been identified in green and ripened
pineapple (11), both the acetate and the corresponding butyrate
reported herein in Mobola plum had also been detected
previously in banana fruit (12). The identification of nitrogen-
containing compounds is noteworthy. While esters of 2-ami-
nobenzoic acid (anthranilic acid) have been found in a few fruits
only, 2-aminobenzaldehyde (1) (Figure 1) is reported herein
for the first time in a natural food, although its application in
fruit flavor compounding has been patented (13). It had been
found previously only in the headspace of some flowers (14),
where it is biosynthesized from indole (15). Likewise, phenyl-
acetaldoxime (2) (Figure 1), also a constituent of certain flower
headspaces (14), has not been found so far in any foodstuff.
The amount of 2 given in Table 1 refers to the sum of syn- and
anti-configurated isomers, taking into account their possible
interconversion during the GC analysis (16). Indeed, the
assignment of aldoxime geometrical isomers by standard GC
is not easy and has not been addressed to date. In the present
case, using gas phase GC/FTIR, we propose that syn-2 (minor;
IR: 962 and 1255 cm-1) is eluted before anti-2 (major; IR:
885 and 1304 cm-1) on a nonpolar stationary phase. Nitro
compounds are very unusual in foods, although (2-nitroethyl)-
benzene (3) (Figure 1), along with other aliphatic nitro
compounds, was detected in the volatile fraction of tomato (17).
Nitro phellandrenes have been found in angelica root essential
oil (18). (2-Nitrobutyl)benzene (4) (Figure 1) is a new natural
product. Its molecular weight (179) was determined by positive
CI/MS, using ammonia as a reactant gas, which makes the
interpretation of the EI mass spectrum straightforward, due to
the loss of 47 mass units from the parent ion and due to the
presence of a base peak at m/z 91. Further evidence was
provided by the IR spectrum, which shows a striking similarity
with that of (2-nitroethyl)benzene (3). Final confirmation of the
structure was provided by direct GC/MS comparison with a
synthetic reference sample (9). Using an appropriate chiral
phase, baseline GC separation of the two enantiomers of 3 can
NMR Analyses. 1H NMR and 13C spectra of synthetic samples were
obtained at 400 and 100.6 MHz, respectively, on a Bruker DPX400
instrument, with chloroform as the internal standard.
Component Identification. Retention indexes were calculated vs
linear aliphatic acid ethyl esters (4), injected in the same chromato-
graphic conditions. Identifications were made by comparing MS and
retention data recorded from authentic reference compounds. Unless
otherwise specified hereafter, all reference compounds are commercially
available (Sigma-Aldrich, Saint Quentin Fallavier, France). 3-(Acety-
loxy)-2-butanone and 3-(butanoyloxy)-2-butanone were obtained from
Berje´ (Bloomfield, NJ) and Northville Labs (Northville, MI), respec-
tively. Ethyl 2-(methylthio)acetate was obtained from Janssen (Titus-
ville, NJ). A number of compounds were prepared for the purpose of
this study by standard or published synthetic procedures: propyl
2-methyl- and 3-methylbutyrates were prepared by reacting the corre-
sponding acid chlorides with 1-propanol. Ethyl 2-methyl-2-pentenoate
and phenylethyl pentanoate and phenylethyl 4-methylpentanoate were
similarly prepared from the corresponding acid chlorides and the
suitable commercially available alcanols. The acid chlorides were
prepared from the commercial acids and redistilled thionyl chloride.
2-Aminobenzaldehyde was prepared from 2-nitrobenzaldehyde (Ald-
rich) by catalytic hydrogenation (5); (2-nitrophenyl)ethane was prepared
by reduction of (2-nitroethenyl)benzene with NaBH4 (6); the latter was
prepared by aldol condensation of nitromethane with benzaldehyde (7);
phenylacetaldoxime (F. 104-106°) was prepared by oximation (8) of
freshly distilled phenylacetaldehyde (Aldrich). (2-Nitrobutyl)benzene
was synthesized by condensing lithiated 1-nitropropane with benzyl
bromide at -90 °C, in 55% yield (9). CAS RN 61668-44-8. MS [m/z
(%)]: 39 (9), 51 (7), 65 (13), 77 (7), 91 (100), 117 (32), 132 (34), 179
1
(<1). H NMR: δ 7.36-7.18 (m, 5 H, Ar protons), 4.66 (dddd, J1 )
9.3 Hz, J2 ) 8.5 Hz, J3 ) 7.5 Hz, J4 ) 5.8 Hz, 1 H, CHNO2), 3.29
(dd, J1 ) 14.2 Hz, J2 ) 8.5 Hz, 1 H, PhCHHCHNO2), 3.06 (dd, J1 )
14.2 Hz, J2 ) 5.8 Hz, 1 H, PhCHHCHNO2), 2.05 (ddt, J1 ) 11.8 Hz,
J2 ) 9.3 Hz, J3 ) 7.4 Hz, 1 H, CH3CHHCHNO2), 1.87 (ddt, J1 ) 11.8
Hz, J2 ) 7.5 Hz, J3 ) 7.4 Hz, 1 H, CH3CHHCHNO2), 1.01 (t, J ) 7.4
Hz, 3H, CH3); these values differ significantly from the published ones
(10). 13C NMR: δ 135.6 (s), 128.80 (2d), 128.77 (2d), 127.3 (d), 91.8
(d), 40.1 (t), 27.2 (t), 10.6 (q). FTIR (gas phase): ν (cm-1) 1563 and
1368 (C-NO2).
RESULTS AND DISCUSSION
2-Phenylethanol is by far the main component of the volatile
fraction of Mobola plum (12-15 ppm in the fresh fruit), and
the bulk of its esters represents about 25% of the remaining
part (Table 1). This accounts for the floral character of the

Volatiles in Mobola Plum
J. Agric. Food Chem., Vol. 52, No. 8, 2004 2325
(3) Le, M.; Pandya, R.; Valuckas, J. Utilization of existing FID
retention index data to identify compounds with a simultaneous
sulfur/nitrogen detector. Communication no. 300-14P presented
at the Pittcon’ 2003, March 9-14, 2003, Orlando, FL.
(4) Shibamoto, T. Retention Indices in Essential Oil Analysis. In
Capillary Gas Chromatography in Essential Oil Analysis;
Sandra, P., Bicchi, C., Eds.; Huethig: Heidelberg, Germany,
1987; pp 259-274.
(5) Smith, L. I.; Opie, J. W. Organic Syntheses; John Wiley and
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borohydride reduction of nitrostyrenes by reverse addition. A
simple and efficient method for the large-scale preparation of
phenylnitroethanes. Synthesis 1985, 886-887.
(7) Furniss, B. S.; Hannaford, A. J.; Smith, P. W. G.; Tatchell, A.
R. Vogel’s Textbook of Practical Organic Chemistry, 5th ed.;
Langman Scientific and Technical: Harlow, United Kingdom,
1989; p 1035.
(8) Furniss, B. S.; Hannaford, A. J.; Smith, P. W. G.; Tatchell, A.
R. Vogel’s Textbook of Practical Organic Chemistry, 5th ed.;
Langman Scientific and Technical: Harlow, United Kingdom,
1989; p 1259.
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doppeldeprotonierten Nitroalkanen.-Erzeugung, Eigenschaften
und Umsetzungen mit Alkyl- und Allylhalogeniden. HelV. Chim.
Acta 1979, 62, 2239-2257.
(10) Jiang, J.; Choo, S. Y.; Omar, N.; Ahamad, N. GC-MS analysis
of volatile compounds in durian (Durio zibethinus Murr.). In
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Mussinan, C. J., Parliment, T. H., Shahidi, F., Spanier, A. M.,
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comosus (L.)]. J. Agric. Food Chem. 1992, 40, 599-603.
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fruit (Musa sapientum L.). J. Agric. Food Chem. 1993, 41,
2056-2062.
be achieved. In using the same column type and GC/MS in
selected ion mode (ion m/z 91), it was possible to observe that
3 occurs in the fruit extract in ca. 50% enantiomeric excess
(ee). However, the enantiomer assignment of this scalemic
mixture and the determination of the ee recovery rate during
the extraction procedure require an authentic sample prepared
by enantioselective means; further work in this direction is in
progress and will be reported elsewhere. The biogenesis of (2-
nitroethyl)benzene (3), as well as its congeners, 2-phenylethanol,
phenylacetaldoxime, and phenylacetonitrile, is related to phe-
nylalanine, whereas the direct formation of (2-nitrobutyl)benzene
(4) from any amino acid precursor is unlikely, although
(2-nitroethyl)benzene is itself a putative intermediate. The odor
of 3 is described as primarily floral, green, with geranium,
tomato, and oily undertones, with an odor threshold of 2 ppb
in water (17). The odor of 4 is sweet, fruity, and berrylike. When
tasted at 1 ppm in water, the flavor is rosy and lycheelike,
whereas at 10 ppm, the flavor is spicy, carrot seed, and
cuminlike with green and woody undertones. Because the
recovery rate of phenylacetaldoxime had previously been shown
to be dependent on the isolation procedure (19), we decided to
undertake a specific investigation on this item and selected other
nitrogen-containing compounds identified in the present study.
The recovery rates of phenylacetonitrile, 2-aminobenzaldehyde
(1), phenylacetaldoxime (2), (2-nitroethyl)benzene (3), and (2-
nitrobutyl)benzene (4) during the vacuum hydrodistillation step
were 68, 25, 4, 72, and 115%, respectively, while the recovery
rates of all five compounds during the extraction step only were
94-116%. These results suggest that the organoleptic contribu-
tion of these compounds in the fruit, especially 1 and 2, might
be significant. Indeed, while the flavor of 1 is similar to that of
ethyl anthranilate when tasted at 3 ppm, the odor of phenyl-
acetaldoxime (2) is reminiscent of phenylacetaldehyde with
orange blossom notes, but its flavor is insignificant when tasted
at 10 ppm or lower.
At least 12 sulfur-containing compounds were selectively
detected using a PFPD. The three main components are ethyl-
(major), methyl-, and propyl 3-(methylthio)propionate. Their
presence was subsequently confirmed in carrying out a selective
search by GC/MS.
In summary, the volatile compounds identified in Mobola
plum make an interesting blend, which suggests original
applications in flavor compounding. Further results concerning
other fruits originating from the same area will be reported in
forthcoming papers.
(13) P. Robertet et Cie. French Patent No. 2,584,926; priority, 22
July 1985.
(14) Joulain, D. Study of the fragrance given off by certain springtime
flowers. In Progress in Essential Oil Research; Brunke, E.-J.,
Ed.; Walter de Gruyter & Co: Berlin, Germany, 1986; pp 57-
67.
(15) Spiteller, P.; Steglich, W. Biosynthesis of 2-aminobenzaldehyde
in flowers of Robinia pseudoacacia and Philadelphia coronarius.
Phytochemistry 2001, 57, 361-363.
(16) Marriott, P.; Trapp, O.; Shellie, R.; Schurig, V. Time-resolved
cryogenic modulation reveals isomer interconversion profiles in
dynamic chromatography. J. Chromatogr. A 2001, 919, 115-
126.
ACKNOWLEDGMENT
(17) Buttery, R. G.; Teranishi, R.; Flath, R. A.; Ling, L. C. Fresh
Tomato Volatiles: Composition and Sensory Studies. In FlaVor
Chemistry: New Trends and DeVelopments; ACS Symposium
Series 388; Teranishi, R., Buttery, R. G., Shahidi, F., Eds.;
American Chemical Society: Washington, DC, 1989; pp 213-
222.
(18) Escher, S.; Keller, U.; Willhalm, B. Neue Phellandren-Derivative
aus dem Wurzelo¨l von Angelica archangelica L. HelV. Chim.
Acta 1979, 62, 2061-2072.
(19) Joulain, D. Cryogenic Vacuum Trapping of Scents from Temper-
ate and Tropical Flowers. In BioactiVe Volatile Compounds from
Plants; ACS Symposium Series 525; Teranishi, R., Buttery, R.
G., Sugisawa, H., Eds.; American Chemical Society: Washing-
ton, DC, 1993; pp 187-204.
We are indebted to Professor Braam van Wik (University of
Pretoria, SA) for the collection and identification of the fruits,
to Professor Raphael Tabacchi and Dr. Saturnin Claude
(University of Neuchaˆtel, Switzerland) for recording the NMR
spectra and providing the chiral GC column, and to Brigitte
Loyer (Robertet) for conducting sensory evaluations.
LITERATURE CITED
(1) Vaghani, S. N.; Chundawat, B. S. Lesser known fruits from
Africa and Asia. In Encyclopaedia of Food Science, Food
Technology and Nutrition; Schroeder, C. A., McRae, R., Rob-
inson, R. K., Sadler, M. J., Eds; Academic Press: London, United
Kigdom, 1993; pp 2126-2134.
(2) Werkhoff, P.; Gu¨ntert, M.; Krammer, G.; Sommer, H.; Kaulen,
J. Vacuum headspace method in aroma research: flavor chem-
istry of yellow passion fruits. J. Agric. Food Chem. 1998, 46,
1076-1093.
Received for review October 10, 2003. Revised manuscript received
January 31, 2004. Accepted February 1, 2004.
JF030702I