ISSN 1330-9862 original scientific paper
(FTB-1474)
Volatile Components from Old Plum Brandies
Vele Te{evi}
1*
, Ninoslav Niki}evi}
2
, Anka Jovanovi}
3
, Dejan Djokovi}
1
,
Ljubodrag Vujisi}
4
, Ivan Vu~kovi}
4
and Mirjana Boni}
5
1
Faculty of Chemistry, University of Belgrade, Studentski trg 16, SCG-11000 Belgrade,
Serbia and Montenegro
2
Faculty of Agriculture, University of Belgrade, Nemanjina 6, SCG-11080 Zemun,
Serbia and Montenegro
3
Institute of Public Health, 29 Novembra 54a, SCG-11000 Belgrade, Serbia and Montenegro
4
Institute for Chemistry, Technology and Metallurgy, University of Belgrade, Njego{eva 12,
SCG-11000 Belgrade, Serbia and Montenegro
5
Institute of Public Health, Zmaj Jovina 30, SCG-2400 Subotica, Serbia and Montenegro
Received: January 25, 2005
Accepted: May 25, 2005
Summary
Gas chromatography and GC/MS methods were used to detect volatile components
of three home-made natural old plum brandy samples and one sample of industrially-pro-
duced plum brandy. Gas chromatography and gas chromatography-mass spectrometric
analysis of this extracts led to the identification of 99 components, including 46 esters, 7
hydrocarbons (alkanes and alkenes), 3 aldehydes, 9 alcohols, 1 lactone, 1 ketone, 8 acetals,
14 terpenes, 8 acids and 2 phenols. Ethyl esters of C
8
–C
18
acids were the most abundant in
all samples. In addition, the content of methanol, ethanol and higher alcohols C
3
–C
5
was
determined.
Key words: plum brandy, aroma, GC/MS, ethyl esters
Introduction
Plum brandy, as a distillate of Prunus crop plum
fermented must, apart from the main elements, ethanol
and water, contains numerous ingredients, the concen
-
tration of which varies within an average of 0.5–1.0 %
depending on the raw material content, the way in
which alcohol fermentation is carried out and the man
-
ner in which distillation is conducted. Apart from nu
-
merous valued components it contains, plum brandy
can also contain some undesirable ingredients. This re
-
fers, first of all, to HCN, ethyl-carbamate and methanol.
However, certain amounts of methanol must be present
in fermented plum must distillates, in respect to the fact
that its presence in them is considered to be a proof and
indicator of authentic, natural, fruit origin.
Aromatic compounds are very important for the
quality and aroma of alcoholic beverages. These com
-
pounds can be classified into four groups: primary aro
-
matic compounds (whose entire aroma appears exactly
as in the fruit during ripening); secondary aromatic
components (formed during alcoholic fermentation); ter
-
tiary aromatic compounds (formed during the distilla
-
tion process); and quaternary aromatic compounds
(formed during the maturation process). In a rich mix
-
ture of alcoholic beverages aromatic compounds are
present in a small percentage.
Chemical compounds that give a beverage its char
-
acteristic flavour and aroma can be determined and
used to classify the beverage as to the type and country
of origin. Such analysis has important applications in
product control and prevention of brand fraud. No sin
-
367
V. TE[EVI] et al.: Volatile Components of Plum Brandies, Food Technol. Biotechnol. 43 (4) 367–372 (2005)
*Corresponding author; Phone: ++381 11 630 474; Fax: ++381 11 636 061; E-mail: vtesevic@chem.bg.ac.yu
gle chemical in an alcoholic beverage is sufficient to dis
-
tinguish one brand from another or to determine its
quality. Various components found in beverages such as
whisky, rum and plum brandy originate from the fer
-
mentation, distillation or ageing stages. Brandy, whisky
and rum contain similar volatile fermentation alcohols.
The concentrations of these components depend on their
substrate of origin and on the yeasts used for fermenta
-
tion (1). During the ageing process, volatile and nonvol
-
atile phenolic compounds may be extracted from oak
ageing barrels. The extent of the extraction depends on
the age, type and size of the barrel (2). Some of the com
-
pounds found in alcoholic beverages may react with one
another, dissociate, evaporate, or be absorbed, whereby
their concentrations change during the ageing process
(3).
Higher aliphatic aldehydes (nonanal and some oth
-
ers), 2-undecanone, benzaldehyde, damascenone, benzyl
acetate, ethyl phenyl acetate, phenyl ethyl acetate, ethyl-
-3-phenylpropionate, methyl cinnamate, ethyl cinnama
-
tes, and several other compounds were the most signifi
-
cant contributors to the typical plum brandy-like flavour
(4).
During the alcoholic fermentation of plum juice ma
-
ny esters can be formed, but the most significant ones
are acetate esters of higher alcohols (ethyl acetate, isoa-
myl acetate, isobutyl acetate and 2-phenyl ethyl acetate)
and ethyl esters of fatty acids (ethyl butyrate, ethyl lac-
tate, ethyl caprinate, ethyl caprylate and ethyl caprona-
te) (5).
Various extraction methods have been widely used
for the analysis of volatile components of fruit brandies,
such as distillation techniques, solvent extraction, solid
phase extraction (SPE), solid phase microextraction
(SPME), and stir bar sorptive extraction (SBSE) (6–8).
Gas chromatography (GC) is a powerful tool in the anal-
ysis of alcoholic beverage products. Minimal sample
preparation, in general, is required, since the samples
are in the liquid state in an alcohol or alcohol/water
matrix. The flavour compounds tend to be volatile in
nature, which fulfills one of the main requirements of
GC. General detectors, such as the flame ionization de
-
tector (FID), or more information-rich detectors, such as
the mass selective detector (MSD), can be used.
The aim of this study was to compare the contents
of volatile compounds in different plum brandies.
Materials and Methods
Four Serbian old plum brandy samples were ana
-
lyzed: (i) plum brandy Manastirka 45 % (sample I), in
-
dustrially produced from Belgrade region, (ii) plum
brandy Sokolova rakija 45 % (sample II), home-made
from U`ice region, (iii) plum brandy Valjevka 45 %
(sample III), home-made from Valjevo region, and (iv)
plum brandy Karanka 45 % (sample IV), home-made
from U`ice region.
Manastirka was distilled in 1990 in modified Cha
-
rente type apparatus for simple distillation with the vol
-
ume of 300 L. Above the apparatus body and cover was
a short rectification column with 4 floors. The purpose
of the column was to concentrate and purify alcohol-
-H
2
O vapours in order to get a distillate with optimum
amounts of ingredients. Sokolova, Valjevka and Karan
-
ka were distilled in 1992, 1997 and 1993, respectively, in
Charente type apparatus for simple distillation with the
volume of 100–150 L. The apparatus for Sokolova and
Karanka did not have a column, only covers. Valjevka
apparatus was suplied with air dephlegmator above the
cover.
All distillates were maturated in oak barrels: Mana
-
stirka, 495 L, casks type Quercus petreae L. (Quercus sessi
-
liflora); Sokolova, 700 L, casks type Quercus pedunculata
(Quercus robur); Valjevka, 505 L, casks type Quercus pe
-
treae L. (Quercus sessiliflora); and Karanka, 1000 L, casks
type Quercus pedunculata (Quercus robur).
GC and GC/MS analysis of volatile compounds
For a typical experiment, a 100-mL aliquot of each
beverage was mixed with 50 mL of dichloromethane
and continuously extracted (2 h). The extract was dried
(2 h) over anhydrous sodium sulfate, and concentrated
to 1.0 mL under nitrogen.
Gas chromatographic analysis was performed using
a gas chromatograph HP 5890 equipped with a flame
ionization detector (FID) and a split/splitless injector.
The separation was achieved using a HP-5 (5 % diphen
-
yl and 95 % dimethylpolysiloxane) fused silica capillary
column,30mx0.25mmi.d.,0.25m film thickness. GC
oven temperature was programmed from 50 °C (6 min)
to 285 °C at a rate of 4.3 °C/min. Hydrogen was used as
carrier gas; flow rate was 1.6 mL/min at 45 °C. Injector
temperature was 250 °C, detector temperature 280 °C,
and injection mode splitless. An injection volume of 1.0
L was used for the beverage extract.
Gas chromatographic-mass spectrometric (GC/MS)
analysis was performed using an Agilent 6890 gas chro-
matograph coupled with an Agilent 5973 Network mass
selective detector (MSD), in positive ion electron impact
(EI) mode. The separation was achieved using an Agi-
lent 19091S-433 HP-5MS fused silica capillary column,
30mx0.25mmi.d.,0.25µmfilmthickness. GC oven
temperature was programmed from 60 to 285 °C at a
rate of 4.3 °C/min. Helium was used as carrier gas, inlet
pressure was 25 kPa, linear velocity was 1 mL/min at
210 °C. Injector temperature was 250 °C, and injection
mode splitless. MS scan conditions: source temperature,
200 °C; interface temperature, 250 °C; E energy, 70 eV;
mass scan range, 40–350 amu (atomic mass units). Iden
-
tification of the components was done on the basis of re
-
tention index and the comparison with reference spectra
(Wiley and NIST databases). Percentage (relative) of the
identified compounds was computed from GC peak
area.
GC analysis of alcohols
Determination of methanol, ethanol and higher al
-
cohols C
3
–C
5
in the old plum brandies was carried out
by adding 2.5 mL of n-butanol 1 as an internal stan
-
dard to 2.5 mL of brandy. Prior to evaluation of ethanol
content each brandy was diluted tenfold with water.
A CE INSTRUMENTS Model 8000
Top
gas chromato
-
graph equipped with a headspace autosampler and fla
-
me ionisation detector (FID) was used. The separation
368
V. TE[EVI] et al.: Volatile Components of Plum Brandies, Food Technol. Biotechnol. 43 (4) 367–372 (2005)
was achieved using a J&W Scientific DB – WAX fused
silica capillary column, 30mx0.32mmi.d.,0.25m
film thickness. GC oven temperature was programmed
from 30 °C (6 min) to 220 °C at the rate of 4.3 °C/min.
Nitrogen was used as carrier gas; flow rate was 1 mL/
min at 210 °C. Injector temperature was 220 °C, while
detector temperature was 250 °C. The samples were in
-
jected with a 164.3 splitting.
Sensory analysis
Sensory assessment of plum brandy samples was
performed using modified Buxbaum model of positive
ranking. This model is based on 5 sensorial experiences
rated by maximum 20 points. The samples of plum
brandies were subjected to sensory evaluation by a
panel comprising 5 qualified testers, all of them highly
experienced in sensory testing.
Results and Discussion
The volatile compounds identified in the four spirits
are presented in Table 1. A total of 71, 71, 81 and 76 free
aroma compounds were identified in the plum brandy
samples I, II, III and IV, respectively, including alcohols,
esters, monoterpene, carbonyl compounds, lactones, ac
-
ids, volatile phenols and acetal compounds.
369
V. TE[EVI] et al.: Volatile Components of Plum Brandies, Food Technol. Biotechnol. 43 (4) 367–372 (2005)
Table 1. Aroma composition of the plum brandies I–IV (%)
Compound I II III IV RI
a
Isoamyl acetate 0.72 0.21 0.11 0.13 876
2-methyl butyl acetate 0.32 0.05 0.07 880
Ethyl pentanoate 0.21 0.07 0.09 898
1,1-diethoxybutane 0.05 0.04
1,1-diethoxy-2-methyl propane 0.12
Methyl hexanoate 0.02 927
-pinene 0.14 939
1,1-diethoxy-3-methyl butane 0.19 0.15 0.15 0.11
Benzaldehyde 1.33 0.97 0.60 0.65 961
Heptanol 0.20 0.07 0.02 969
-myrcene 0.15 991
Ethyl hexanoate 3.08 1.62 1.36 1.33 996
p-cymene 0.21 0.03 0.04 1026
Limonene 0.02 0.01 1031
Benzyl alcohol 0.36 0.06 0.05 0.07 1060
-terpinene 0.26 0.03 1062
Pentyl cyclopropane 0.17 0.02
c-linalool oxide 0.11 0.05 0.02 0.08 1074
1,1,3-triethoxypropane 0.20 0.04 0.05
t-linalool oxide 0.04 0.08 1088
1,1-diethoxyhexane 0.08 0.34 0.32 0.42
Ethyl heptanoate 0.03 0.04 0.02 1095
Linalool 0.12 0.03 0.05 1098
Nonanal 0.30 0.93 0.53 0.51 1098
-phenyl ethyl alcohol 0.37 0.09 0.05 0.10 1110
Methyl octanoate 0.13 0.11 0.11 0.09 1125
Benzyl acetate 0.03 0.01 1163
Ethyl benzoate 13.46 4.35 2.32 4.10 1170
1,1-diethoxyheptane 0.08 0.14 0.08 0.06
-terpineol 0.20 0.06 0.05 1189
Ethyl octanoate 9.99 6.36 6.34 6.23 1195
Decanal 0.03 0.03 0.03 1204
Methyl nonanoate 0.03 0.03 1225
Citronellol 0.03 0.03 1228
t-geraniol 0.04 0.04 0.01 0.01 1255
Ethyl salicylate 2.37 1.19 0.74 1.20 1267
1,1-diethoxyoctane 0.05 0.14
Ethyl nonanoate 1.61 1.66 1.62 2.23
Methyl decanoate 0.18 0.26 0.35 0.35 1326
2-methyl propyl benzoate 0.09 0.03
Isobutyl octanoate 0.01 0.01
Ethyl-3-phenylpropionate 0.60 0.29 0.13 0.65
370
V. TE[EVI] et al.: Volatile Components of Plum Brandies, Food Technol. Biotechnol. 43 (4) 367–372 (2005)
Compound I II III IV RI
a
Eugenol 0.58 0.78 0.49 0.72 1356
2-methoxy-4-propylphenol 0.03 0.09
Decanoic acid 1.26 0.12 0.91
1,1-diethoxynonane 3.13 0.49
Ethyl-9-decanoate 0.13 0.11
Ethyl decanoate 14.03 14.89 15.25 19.88 1394
Methyl eugenol 0.15 1401
3-methyl butyl benzoate 0.20 0.10 0.07 0.18 1430
Isoamyl octanoate 0.04 0.10 0.10 0.14 1446
Dihydro--ionol 0.11 0.02 0.08
4-methoxy ethyl benzoate 0.05 0.01
Undecanoic acid 0.01
Ethyl cinnamate 1.27 0.72 0.46 0.87 1462
1-dodecanol 0.08 0.08 0.02 0.05 1473
Propyl decanoate 0.06 0.05 0.05 0.06
Ethyl undecanoate 0.14 0.15 0.24 1496
Ethyl-2,2-decadienoate 0.08
-muurolene 0.06 0.08 1499
Pentadecane 0.09 0.01 0.05 1500
Methyl dodecanoate 0.14 0.25 0.31 1525
Isobutyl decanoate 0.10 0.09 0.09
Dodecanoic acid 3.32 0.83 1.79 3.73 1568
Hexyl benzoate 0.02 1576
Ethyl dodecanoate 5.63 12.06 13.42 17.03 1576
Anisyl-isobutyrate 0.25 0.05 0.03 0.04
Nerolidol 0.01 1564
3-methyl butyl decanoate 0.06 0.26 0.27 0.35
6,9-pentadecadien-1-ol 0.14
1,13-tetradecadiene 0.10 0.09 0.03
Bisabolol oxide 0.09 0.05 1635
Cyclotetradecane 0.11 0.10 0.12 0.19
-dodecalactone 0.26 0.14 0.10 0.11 1647
Ethyl tridecanoate 0.09 0.13 0.11 0.09
2-pentadecanone 0.04 0.05
Heptadecane 0.02 0.04 1700
Methyl tetradecanoate 0.14 0.13 0.14 0.20 1727
Tetradecanoic acid 0.21 1.64 1.90 1.82
Cyclotetradecane 0.04 0.04
9-hexadecenoic acid 0.15 0.19 0.13
Ethyl tetradecanoate 1.29 3.90 4.35 3.99 1793
3-methyl butyl dodecanoate 0.10 0.53 0.42 0.27
2-phenyl ethyl octanoate 0.01 0.01 0.02
1-nonadecanol 0.07 0.14 0.12 0.10
Ethyl pentadecanoate 0.11 0.23 0.33 0.24
Methyl 9-hexadecenoate 0.05 0.05 0.03
Methyl hexadecanoate 0.14 0.27 0.41 0.23 1927
Hexadecanoic acid 0.66 0.24 0.55 0.39 1968
Ethyl-9-hexadecenoate 0.75 2.22 2.18
Eicosane 0.05 0.02 2000
Ethyl hexadecenoate 4.59 10.37 13.87 6.93 1993
2-phenyl ethyl octanoate 0.04 0.03 0.02
9,12-octadecadienoic acid 0.09 0.25 0.32 0.13 2092
9,12,15-octadecatrienoic acid 0.03
0.10
0.13 0.19
Hexadecane-1,2-diol 0.20 0.25 0.37
Ethyl linoleate 4.48 6.30 9.72 5.16 2177
Ethyl oleate 4.56 2180
Ethyl stearate 0.39 0.55 1.35 0.29 2194
a
Retention index on DB-5 and according to n-paraffins
General composition of plum brandies was in accor
-
dance with previous studies carried out on Yugoslavian
plum brandy (9).
Ethyl esters of C
8
–C
18
fatty acids were the most
abundant in all samples. Fatty acid esters contribute to
the flavour of the destillates with a pleasant fruity and
flowery smell (10), indicative of the quality of the spirit
(11). Among these, ethyl decanoate is the most abun
-
dant of all esters. The ethyl esters, which are produced
during the fermentation of raw materials, are transfer
-
red to the spirits and their content increases during ag
-
ing (12). Isoamyl acetate, 2-methyl butyl acetate and ben
-
zyl acetate constitute the acetic acid ester group, which
are mostly responsible for the flowery and fruity aroma
of the distillates (13). Table 1 shows that isoamyl acetate
is present in the highest concentration among these
three acetates.
Long chain fatty acids, decanoic, dodecanoic, tetra-
decanoic, and hexadecanoic acid have less strong effect
on the flavour of the distillates (11,14). Table 1 shows
that hexanoic acid has the highest mean value of all
these acids, followed by dodecanoic acid, decanoic acid
and tetradecanoic acid.
The oldest plum brandy (sample I) contained higher
concentration of some ingredients than other two (sam
-
ple II and III), such as: benzaldehyde, ethyl benzoate,
ethyl salicylate and ethyl cinamate. Also, benzyl alcohol
and -phenyl ethyl alcohol, which are known aromatic
alcohols, were found at higher concentrations in the
sample I. -phenyl ethyl alcohol introduces a pleasant
aroma to distillates, resembling to rose (15).
The aromatic terpene compounds, -pinene and
-myrcene, were detected only in sample I. Eugenol,
with an aroma of cloves, was detected in all samples
and therefore is very important for the aroma of these
spirits. Significant differences were not found for the
mean concentration of eugenol in the spirits from these
four plum brandies.
Ethanol content is very important for the mouthfeel
and flavour of alcoholic beverages. Ethanol content of
brandies ranges from 38–45 % (Table 2).
Sensory evaluation
The results of the sensory evaluations of the four
plum brandy samples are given in Table 3. Total sen
-
sory quality of plum brandies is between 18.10 and
18.60, which is a very high score. According to the re
-
sults of the performed sensory ranking, the best rated
brandy is sample I, which was rated with very high sco-
re by 5 examiners (total sensory characteristics 18.60).
These diferences between apparatus style and heteroge-
neous maturation conditions cause different sensorial
evaluations of brandies.
Conclusions
The obtained results have shown that the produc
-
tion of plum brandies has significant influence on the
aroma constituents and the quality of brandies. Changes
in the distillation system and aging time induce consid
-
erable modifications to the volatile composition of plum
brandies. Besides the esters, fatty acids, and fusel alco
-
hols already identified in many types of spirits, other
volatile compounds have been identified. Some terpene
compounds, such as limonene, -myrcene, -pinene,
-terpineol, -terpinene, cis/trans linalool oxide, linalool,
t-geraniol, citronellol, -muurolene and nerolidol, were
identified for the first time in this type of spirit. These
compounds may originate from the plum.
References
1. A. Herranz, P. de la Serna, C. Barro, P.J. Martin, M.D. Ca
-
bezudo, Application of the statistical multivariate analysis
to the differentiation of whiskies of different brands, Food
Chem. 31 (1989) 73–81.
2. S.J. Withers, J.R. Piggott, J.M. Conner, A. Paterson, Com
-
parison of Scotch malt whisky maturation in oak miniatu
-
re casks and American standard barrels, J. Inst. Brew. 101
(1995) 359–364.
3. P.J. Lehtonen, L.A. Keller, E.T. Ali-Mattila, Multi-method
analysis of matured distilled alcoholic beverages for brand
identification, Z. Lebensm. Unters. Forsch. A, 208 (1999)
413–417.
371
V. TE[EVI] et al.: Volatile Components of Plum Brandies, Food Technol. Biotechnol. 43 (4) 367–372 (2005)
Table 2. Content of ethanol, methanol and high alcohols in
plum brandies (I–IV)
Sample
j(ethanol)
j(methanol)
j(higher alcohols C
3
–C
5
)
b
I 38.64 0.22 0.14
II 38.50 0.13 0.09
III 44.95 0.54 0.16
IV 45.56 0.44 0.19
b
Total content of n-propanol, isobutanol, isoamyl alcohol and
n-pentanol
Table 3. Sensory analyses of the old plum brandies
Plum brandy
samples
Assessment characteristics
Colour
(max 1 pts)
Clearness
(max 1 pts)
Distinction
(max 2 pts)
Odour
(max 6 pts)
Taste
(max 10 pts)
Total
(max 20 pts)
Manastirka 1 1 2 5.6 9.0 18.6
Sokolova rakija 1 1 2 5.3 8.8 18.1
Valjevka 1 1 2 5.4 8.9 18.3
Karanka 1 1 2 5.3 8.8 18.1