(5 E/ Z,7 E,9)-Decatrien-2-ones, Pineapple-like Flavors from Fomitopsis betulina - Structure Elucidation and Sensorial Properties

Article abstract of DOI:10.1021/acs.jafc.9b06105

During the cultivation of the edible mushroom Fomitopsis betulina on agro-industrial side streams, a pleasant flavor strongly reminiscent of pineapple was perceived. Aroma extract dilution analyses identified two flavor components with a distinct pineapple odor. On the basis of mass spectrometric data, a Wittig reaction of (E)-penta-2,4-dien-1-yltriphosphonium bromide with ethyl levulinate was conducted. The resulting (5E/Z,7E,9)-decatrien-2-ones were identical to the compounds isolated from the fungal culture. Some structurally related methyl ketones were synthesized, confirmed by nuclear magnetic resonance and mass spectrometry, and their odor was characterized. The lowest odor threshold and most characteristic pineapple-like odor was found for (5Z,7E,9)-decatrien-2-one. Global minimum energy calculation of the methyl ketones and the comparison to (1,3E,5Z)-undecatriene, a character impact compound of fresh pineapple, showed that a chain length of at least 10 carbon atoms and a terminal double bond embedded in a "L"-shaped conformation were common to compounds imparting an intense pineapple-like odor. Both (5E/Z,7E,9)-decatrien-2-ones have not been described as natural flavor compounds.

Full text of DOI:10.1021/acs.jafc.9b06105

Subscriber access provided by LUNDS UNIV
Chemistry and Biology of Aroma and Taste
(5E/Z,7E,9)-Decatrien-2-ones, Pineapple-like Flavors from
Fomitopsis betulina - Structure Elucidation and Sensorial Properties
Miriam Grosse, Tim Pendzialeck, Jörg Fohrer, Ralf G. Berger, and Ulrich Krings
J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.9b06105 • Publication Date (Web): 25 Nov 2019
Downloaded from pubs.acs.org on December 1, 2019
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a service to the research community to expedite the dissemination
of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in
full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully
peer reviewed, but should not be considered the official version of record. They are citable by the
Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore,
the “Just Accepted” Web site may not include all articles that will be published in the journal. After
a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web
site and published as an ASAP article. Note that technical editing may introduce minor changes
to the manuscript text and/or graphics which could affect content, and all legal disclaimers and
ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or
consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W.,
Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the
course of their duties.

Page 1 of 31
Journal of Agricultural and Food Chemistry
(5E/Z,7E,9)-Decatrien-2-ones, Pineapple-like Flavors from Fomitopsis
betulina - Structure Elucidation and Sensorial Properties
Miriam Grosse*1, Tim Pendzialeck1, Jörg Fohrer2, Ralf G. Berger1, Ulrich Krings1
1 Institute of Food Chemistry, Gottfried Wilhelm Leibniz University, Callinstr. 5, 30167
Hannover
2 Institute of Organic Chemistry, Gottfried Wilhelm Leibniz University, Schneiderberg.
1B, 30167 Hannover
*Correspondence to: miriam.grosse@lci-uni-hannover.de, + 49511 762 17257
1
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 2 of 31
1
ABSTRACT
2
3
During the cultivation of the edible mushroom Fomitopsis betulina on agro-industrial
side streams, a pleasant flavor strongly reminiscent of pineapple was perceived.
Aroma extract dilution analyses identified two flavor components with a distinct
pineapple odor. Based on mass spectrometric data, a Wittig reaction of (E)-penta-2,4-
dien-1-yltriphosphonium bromide with ethyl levulinate was conducted. The resulting
(5E/Z,7E,9)-decatrien-2-ones were identical to the compounds isolated from the fungal
culture. Some structurally related methyl ketones were synthesized, confirmed by NMR
and MS, and their odor characterized. The lowest odor threshold and most
characteristic pineapple-like odor was found for (5Z,7E,9)-decatrien-2-one. Global
minimum energy calculation of the methyl ketones and the comparison with (1,3E,5Z)-
undecatriene, a character impact compound of fresh pineapple, showed that a chain
length of at least ten carbon atoms and a terminal double bond embedded in an “L”-
shaped conformation were common to compounds imparting an intense pineapple-like
odor. Both (5E/Z,7E,9)-decatrien-2-ones have not been described as natural flavor
compounds.
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Keywords: Pineapple flavor, (5E/Z,7E,9)-decatrien-2-ones, structure-activity
relationship
20
2
ACS Paragon Plus Environment

Page 3 of 31
Journal of Agricultural and Food Chemistry
21 INTRODUCTION
22
23
24
25
26
27
28
29
30
31
32
Pineapple is one of the most popular tropical fruits because of its unique flavor.
More than 380 volatiles including esters, heterocycles and polyunsaturated
hydrocarbons were reported.1–3 The key aroma compounds are 4-hydroxy-2,5-
dimethyl-3(2H)-furanone, ethyl-2-methylbutanoate, ethyl-2-methylpropanoate, methyl-
2-methylbutanoate and (1E/Z,3,5)-undecatriene.2 Takeoka et al. stated that besides
the key aroma compounds ethyl acetate, ethyl butanoate, ethyl hexanoate, ethyl 2-
methylpropanoate, methyl hexanoate and methyl butanoate are required to create the
exotic sweet flavor of fresh pineapple, whereas Pino stated that solely the addition of
ethyl 3-(methylthio)propanoate and (1,3E,5Z,8Z)-undecatetraene was required.4–6
However, a characteristic genuine impact compound, such as vanillin for vanilla, has
not yet been identified.
33
34
35
36
37
38
39
40
During the cultivation of numerous basidiomycetous fungi on various agro-
industrial side streams the formation of a pleasant flavor, strongly reminiscent of
pineapple and honey, was perceived in cell cultures of the edible mushroom
Fomitopsis betulina (formerly Piptoporus or Polyporus betulinus) when grown on
cabbage cuttings. Aroma extract dilution analyses resulted in the identification of six
important flavor components, among them one with distinct pineapple odor.7 Hence,
the fungi generated an aroma compound that evoked a strong pineapple odor
impression on its own.
41
42
43
44
45
The aims of this study were to elucidate the unknown chemical structure of the
flavor compounds based on total synthesis, to determine their sensory properties and
to model the structure-activity relationship based on analogues synthesized using the
same route. This work not only identified a new impact aroma compound, but also
contributes to the understanding of pineapple flavor perception.
3
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 4 of 31
46 MATERIALS AND METHODS
47
48
49
50
Chemicals and substances. Chemicals used were purchased in p.a. quality
from Carl Roth (Karlsruhe, Germany) and Merck (Darmstadt, Germany). Dec-9-en-2-
one was from Sigma-Aldrich (St. Louis, Missouri, USA) in a quality > 95 % and used
without further purification. All solvents were purified in house by rectification.
51 Synthesis of (5E/Z,7E,9)-decatrien-2-ones and structural related
52 compounds
53
54
55
56
57
58
59
60
(5E)-Bromopenta-1,3-diene (1). To a hydrogen bromide (HBr) solution
(3.4 mL, 48 % (v/v), 30.3 mmol) at 5 °C penta-1,4-dienol (2.50 g, 98 %, 29.1 mmol)
was added dropwise within 5 min and the reaction mixture was stirred for another 3 h
at room temperature (RT). During this time diethyl ether (8 mL) and another portion of
hydrogen bromide were added. Afterwards the organic layer was separated, washed
with cold water (3 x 10 mL) and dried over magnesium sulphate (MgSO4). After
filtration the solvent was removed under reduced pressure using a rotary evaporator.
The product (3.82 g, 26.0 mmol, 89 % yield) was obtained as a yellow oil.
61
RI: 1250 (DB-WAX UI), 885 (VF-5ms)
62
63
EI-MS: (C5H7Br, M = 147 g mol-1): m/z (%) = 148 (M+·, 11), 146 (M+·, 11), 94 (1), 92
(1), 81 (2), 79 (2), 67 (100), 65 (15), 51 (4), 41 (39), 39 (25).
64
65
66
67
68
69
(E)-Penta-2,4-dien-1-yltriphenylphosphonium
bromide
(2).
(5E)-
Bromopenta-1,3-diene (5.18 g, 35.2 mmol) was added dropwise to a mixture of
triphenylphosphine (9.85 g 98.5 % (v/v), 37.0 mmol) dissolved in toluene (23 mL)
under nitrogen atmosphere. After stirring the mixture at room temperature for 22 h the
crystalline (E)-penta-2,4-dien-1-yltriphenylphosphonium bromide was separated via
filtration (10.75 g, 26.3 mmol, 75 % yield) as a colourless solid.
4
ACS Paragon Plus Environment

Page 5 of 31
Journal of Agricultural and Food Chemistry
70
71
ESI(+)-MS/MS: (C23H22P, M+ = 329 g/mol): m/z (%) = 329 (M+, 10), 262 (100), 185
(13), 183 (50), 108 (87), 107 (6), 67 (13).
72
73
74
75
76
77
78
79
Ethyl-3-(2-methyl-1,3-dioxolan-2-yl)propanoate (3). A solution of ethyl
levulinate (10.0 g, 69.4 mmol), ethylene glycol (7.0 ml, 125.5 mmol), and p-
toluenesulfonic acid monohydrate (0.13 g, 0.7 mmol) in cyclohexene (40 mL) was
heated in a Dean-Stark apparatus for 4 h under reflux. After cooling to RT saturated
sodium hydrogen carbonate solution (NaHCO3) (20 mL) was added. The organic
phase was washed with water (3 x 20 ml) and dried over MgSO4. The solvent was
removed with a rotary evaporator and the product (5.41 g, 91 % purity, 28.7 mmol,
41 % yield) was obtained as a colorless oil.8
80
81
EI-MS: (C9H16O4, M = 188 g/mol): m/z (%) = 173 (18), 143 (30), 129 (4), 99 (48), 87
(100), 45(3), 43 (35)
82
83
84
85
86
87
88
89
90
91
92
93
3-(2-Methyl-1,3-dioxolan-2-yl)propanal (4). Under N2-atmosphere the acetal
(3) (2.50 g, 13.3 mmol) was dissolved in dry dichloromethane (DCM, 74 mL) at -78 °C.
To this solution 13.9 mL 1 M diisobutyl aluminiumhydride (DIBAL, 13.9 mmol) in n-
hexane was added dropwise. After 45 min under continuous stirring at -78 °C, 2.5 ml
methanol (MeOH) and 10.0 mL saturated sodium chloride solution (NaCl) were added
and stirred for another 1 h at the same temperature. Then the reaction mixture was
stirred over night at RT. After addition of 12.5 g Na2SO4 and stirring for 1 h the organic
phase was filtered, the filter washed with DCM (3 x 10 ml) and finally the solvent was
removed with the rotary evaporator. The residue was purified by flash chromatography
(silica gel, elution with pentene/diethyl ether (PE; 1:1.12 n/n) and diethyl ether (DE),
PE 3:1  DE). The purified product (1.13 g, 7.8 mmol, 59 % yield) was obtained as a
colorless oil.9
94
RI: 1623 (DB-WAX UI), 1079 (VF-5ms)
5
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 6 of 31
95
96
EI-MS: (C7H12O3, M = 144 g/mol): m/z (%) = 129 (27), 87 (100), 85 (26), 71 (6), 57 (7),
55 (11), 43 (64).
97
98
2-Methyl-2-((5E)-octa-3,5,7-trien-1yl)-1,3-dioxolane (5a,b). Under N2-
atmosphere the aldehyde (4) (0.50 g, 3.5 mmol) and the phosphonium salt (2) (1.56 g,
3.8 mmol) were dissolved in dry dimethyl formamide (DMF, 8 mL). After dropwise
addition of sodium methanolate (0.7 mL, 30 % in methanol, 3.6 mmol) at 5 °C the
reaction mixture was stirred for 2 h at constant temperature. Saturated ammonium
chloride solution (NH4Cl, 30 mL) and n-hexane (30 ml) were added prior to filtration.
The organic phase of the filtrate was separated and the aqueous phase was extracted
with n-hexane (3 x 30 mL). The combined organic phase was washed with water and
saturated NaCl-solution (3 x 30 mL each), dried over MgSO4 and then mixed with
butylated hydroxyl toluene (BHT, 10 mg) for stabilization. The solvent was removed
with a rotary evaporator under reduced pressure and the residue was purified by flash
chromatography (silica gel, elution PE, PE 20:1  PE 8:1). The purified product
(0.51 g, 2.6 mmol, 76 % yield) was obtained as a light yellow oil.8
99
100
101
102
103
104
105
106
107
108
109
110
111
3(Z)-Isomer (5b)
RI: 1948 (DB-WAX UI), 1462 (VF-5ms)
112
113
EI-MS: (C12H18O2, M = 194 g/mol): m/z (%) = 194 (M+·, 19), 179 (7), 93 (19), 91 (35),
87 (100), 79 (16), 77 (27), 43 (75).
114
115
3(E)-Isomer (5a)
RI: 1991 (DB-WAX UI), 1487 (VF-5ms)
116
117
EI-MS: (C12H18O2, M = 194 g/mol): m/z (%) = 194 (M+·, 22), 179 (7), 93 (23), 91 (39),
87 (100), 79 (16), 77 (30), 43 (78).
6
ACS Paragon Plus Environment

Page 7 of 31
Journal of Agricultural and Food Chemistry
118
119
120
121
122
123
124
125
126
(5 E/Z,7E,9)-Decatrien-2-one (6a,b). To a mixture of 3 ml perchloric acid
(HClO4, 35 %) and 1 ml DE at 5 °C, 2 mL of a solution of acetal (5a,b) in DE (0.20 g,
1 mmol) was added dropwise within 10 min. After 20 min at constant temperature
(5 °C) the reaction mixture was neutralized with saturated NaHCO3-solution. The
organic phase was separated and the aqueous phase was extracted with DE
(3 x 20 mL). The combined organic phase was washed with water and saturated NaCl-
solution (3 x 30 mL), dried over MgSO4 and stabilized with BHT (10 mg). The residue
was purified by flash chromatography (silica gel, elution with PE 10:1). The purified
product (57 mg, 0.38 mmol, 37 % yield) was obtained as a colorless oil.8
127
128
5(Z)-Isomer (6b)
RI: 1826 (DB-WAX UI), 1268 (VF-5ms)
129
130
EI-MS: (C10H14O, M = 150 g/mol): m/z (%) = 150 (M+·, 35), 135 (1), 107 (16), 93 (14),
91 (81), 79 (57), 71 (3), 67 (11), 65 (18), 43 (100).
131
132
5(E)-Isomer (6a)
RI: 1846 (DB-WAX UI), 1278 (VF-5ms)
133
134
EI-MS: (C10H14O, M = 150 g/mol): m/z (%) = 150 (M+·, 37), 135 (1), 107 (16), 93 (15),
91 (81), 79 (55), 71 (3), 67 (11), 65 (18), 43 (100).
135
136
137
138
139
140
1H-NMR (6a,b):
(400 MHz, CDCl3): δ 2.14, 2.14 (sa,b, 6H, 1a,b), 2.35-2.49 (m, 4H,
4a,b), 2.51-2.55 (m, 4H, 3a,b), 5.05, 5.10 (da,b, J1 = 10.09 Hz,
J2 = 10.25 Hz, 2H, 10a,b), 5.18, 5.23 (da,b, J1 = 16.70 Hz,
J2 = 16.82 Hz, 2H, 10a,b), 5.42 (dt, J1 = 7.47 Hz, J2 = 10.68 Hz,
1H, 5b), 5.69 (dt, J1 = 7.01 Hz, J2 = 14.76 Hz, 1H, 5a), 6.01- 6.03
(m, 8H, 6a,b, 7a,b, 8a,b, 9a,b).
7
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 8 of 31
141
142
143
13C-NMR (6a,b): (100 MHz, CDCl3): δ 22.3, 27.0, 30.1, 43.2, 43.5, 116.9, 117.6,
128.2, 129.5, 130.9, 131.2, 133.2, 133.6, 133.9, 137.1, 137.2,
208.06, 208.14.
144
145
146
147
5,9-Decadien-2-one (7a,b). This compound was synthesized along the same
route as the decatrienones (6a,b) with pent-4-en-1-yltriphosphoniumbromide used in
the Wittig reaction. The product (100 mg, 0.6 mmol, 53 % yield) was obtained as a
colorless oil.8
148
149
5(Z)-Isomer (7b)
RI: 1582 (DB-WAX UI), 1171 (VF-5ms)
150
151
EI-MS: (C10H16O, M = 152 g/mol): m/z (%) = 152 (M+·, 1), 111 (5), 109 (2), 97 (1), 94
(14), 81 (2), 79 (13), 71 (4), 43 (100), 41 (12).
152
153
5(E)-Isomer (7a)
RI: 1173 (VF-5ms)
154
155
EI-MS: (C10H16O, M = 152 g/mol): m/z (%) = 152 (M+·, 1), 111 (5), 109 (2), 97 (1), 94
(12), 81 (2), 79 (10), 71 (3), 43 (100), 41 (10).
156
157
158
5-Decen-2-one (8a,b). This compound was synthesized along the same route
as the decatrienones (6) with pentyltriphosphoniumbromide used in the Wittig reaction.
The product (70 mg, 0.45 mmol, 67 % yield) was obtained as a colorless oil.8
159
160
5(Z)-Isomer (8b)
RI: 1530 (DB-WAX UI), 1179 (VF-5ms)
161
162
EI-MS: (C10H16O, M = 152 g/mol): m/z (%) = 152 (M+·, 1), 111 (5), 109 (2), 97 (1), 94
(14), 81 (2), 79 (13), 71 (4), 43 (100), 41 (12).
163
5(E)-Isomer (8a)
8
ACS Paragon Plus Environment

Page 9 of 31
Journal of Agricultural and Food Chemistry
164
RI: 1183 (VF-5ms)
165
166
EI-MS: (C10H16O, M = 152 g/mol): m/z (%) = 152 (M+·, 1), 111 (5), 109 (2), 97 (1), 94
(12), 81 (2), 79 (10), 71 (3), 43 (100), 41 (10).
167
168
169
170
171
172
(5,7E)-Nonadien-2-one (9a,b). This compound was synthesized along the
same synthetic route as the decatrienones (6) with (E)-buten-2-en-1-
yltriphosphoniumbromide used in the Wittig reaction. A product mixture of 9a,b (80 mg,
81 % purity, 0.47 mmol, 59 % yield) and its constitutional isomer, 6-methylocta-5,7(E)-
dien-2-one, 10a,b (80 mg, 16 % purity, 0.092 mmol, 59 % yield) was obtained as a
light yellow oil.8
173
174
5(Z)-Isomer (9b)
RI: 1596 (DB-WAX UI), 1139 (VF-5ms)
175
176
EI-MS(C9H14O, M = 138 g/mol): m/z (%) = 138 (M+·, 29), 123 (5), 95 (41), 81 (31), 79
(38), 67 (29), 55 (21), 43 (100), 41 (22).
177
178
5(E)-Isomer (9a)
RI: 1605 (DB-WAX UI), 1145 (VF-5ms)
179
180
EI-MS: (C9H14O, M = 138 g/mol): m/z (%) = 138 (M+·, 31), 123 (5), 95 (40), 81 (32), 79
(38), 67 (28), 55 (20), 43 (100), 41 (21).
181
182
5(Z)-Isomer (9c)
RI: 1613 (DB-WAX UI), 1150 (VF-5ms)
183
184
EI-MS(C9H14O, M = 138 g/mol): m/z (%) = 138 (M+·, 27), 123 (5), 95 (40), 81 (29), 79
(38), 67 (27), 55 (20), 43 (100), 41 (21).
185
186
5(E)-Isomer (9d)
RI: 1617 (DB-WAX UI), 1154 (VF-5ms)
9
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 10 of 31
187
188
EI-MS: (C9H14O, M = 138 g/mol): m/z (%) = 138 (M+·, 23), 123 (5), 95 (40), 81 (28), 79
(37), 67 (27), 55 (20), 43 (100), 41 (21).
189
190
191
5,7-Octadien-2-one (10a,b). This compound was synthesized along the same
route as the decatrienones (6) with allyltriphosphoniumbromide used in the Wittig
reaction. The product (80 mg, 0.47 mmol, 59 % yield) was obtained as a colorless oil.8
192
193
194
195
5(Z)-Isomer (10b)
RI: 1463 (DB-WAX UI)
5(E)-Isomer (10a)
RI: 1465 (DB-WAX UI)
196
197
EI-MS (E) und (Z) isomers: (C8H12O, M = 124 g/mol): m/z (%) = 124 (M+·, 12), 109 (5),
81 (33), 79 (22), 71 (1), 67 (20), 53(12), 43 (100).
198
199
200
201
202
203
204
205
206
207
208
209
Purification of the (5E,7E,9)-Decatrien-2-one (6a). Product purification was
performed via preparative gas chromatography. A Hewlett-Packard 5890 (Hewlett-
Packard, Palo Alto) gas chromatograph equipped with a HP 7673 auto sampler
(Hewlett-Packard, Palo Alto), a cold injection system (CIS 3; Gerstel, Mülheim,
Germany) and a multi column switching system II (Gerstel, Mülheim, Germany).
Separation was performed on a polar Optima-Wax precolumn (5 m, 0.53 mm, 2 µm,
Macharey & Nagel Düren, Germany) and an Optima Wax preparative column (25 m,
0.53 mm, 2 µm, Macherey & Nagel Düren, Germany) with a hydrogen flow of
8.9 mL/min. For separation, the following temperature program was used: 40 °C hold
for 3 min; 1 °C min-1 until 168 °C, 20 °C min-1 until 240 °C held for 15 min. The product
was collected with the multi column switching system II. The purified product was used
for NMR characterization.
10
ACS Paragon Plus Environment

Page 11 of 31
Journal of Agricultural and Food Chemistry
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
Gas chromatography mass spectrometry. All products synthesized with the
exception of the respective Wittig salts were diluted to an appropriate concentration
with diethyl ether and analyzed by means of high resolution capillary gas
chromatography coupled to a mass selective detector (GC-MS). GC-analyses were
performed on two stationary phases of different polarity. Retention indices were
calculated according to Van den Dool and Kratz using homologue alkanes from C8 to
C30. Samples (0.5 µL) were injected on-column.10 The GC-MS device consisted of a
7890B GC-system (Agilent Technologies, Santa Clara) combined with an Agilent
5977A mass selective detector (interface: 230 °C, ion source: 200 °C, quadrupole:
100 °C, electron impact ionization: 70 eV, scan range m/z 33–300 amu; Agilent
Technologies, Santa Clara). Stationary phases DB-WAX UI (30 m, 0.25 mm, 0.25 µm,
Agilent J&W GC Columns, Santa Clara) and VF-5ms (30 m, 0.25 mm, 0.25 µm, Agilent
J&W GC Columns, Santa Clara) were installed. All analyses were performed with a
volumetric flow rate of 1 mL/min Helium using the following temperature programs:
40 °C hold for 3 min; 8 °C/min until 230 °C, 230 °C hold for 10 min (DB-WAXms) and
40 °C hold for 3 min, 8 °C/min until 230 °C, 25 °C/min until 325 °C, 325 °C hold for
10 min (VF 5ms).
227
228
229
230
231
High resolution GC was done with an Agilent 6890 gas chromatograph equipped
with an Quasar AMD (electron impact ionization: 70 eV scan range m/z 33–500 amu;
Agilent Technologies, Santa Clara). Separation was performed on a DB WAX column
(30 m, 0.32 mm, 0.25 µm, Agilent J&W GC Columns, Santa Clara) using the conditions
as described above.
232
233
234
Gas chromatography Olfactometry. Sensory evaluation and determination of
the perception threshold mass of the decatrien-2-ones was carried out using GC-
Olfactometry (GC-O) combined with aroma extract dilution analysis. The same
11
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 12 of 31
235
236
237
238
239
240
241
242
243
244
chromatographic conditions were used as described, but with hydrogen as the carrier
gas. The effluent was splitted at the end of the column (1:1). One part was directed
towards a flame ionization detector (FID), the second towards the olfactory detection
port (ODP) where the effluent was sniffed by panelists (five trained subjects). The stock
solution contained all synthesized compounds and the commercial 9-decen-2-one (0.1
g/L in DE). Sensory evaluation started with a 1:10 dilution of the stock solution and
was continued with further 1:10 dilution steps until no odor of any of the flavor
compounds was perceived. The individual thresholds were expressed as the ultimate
mass (mT) injected effectively on-column which was still perceived by the majority of
the panelists. The median of the individual thresholds was calculated.
245
246
247
248
249
250
251
252
253
254
255
256
257
258
High performance liquid chromatography tandem mass spectrometry
(HPLC-MS2). The synthesis of Wittig salts was confirmed using high performance
liquid chromatography coupled to a triple quadrupole mass analyzer (Varian 212 LC
pump, Pro Star 325 UV/Vis detector, 320 TQ-MS mass spectrometer). The MS was
conducted in the ESI positive (ESI(+)) mode with the selective mass of the respective
Wittig cation for the first quadrupole and a scan range of m/z 50 to the respective mass
of the cation in the third quadrupole. MS parameters were: capillary voltage +40 V,
needle voltage 5000 V, nebulizer gas (N2) 379 kPa, drying gas 207 kPa at 350 °C. The
collision cell was operating with 267 mPa Argon as the collision gas and 40 V collision
energy. For HPLC, water and acetonitrile (MS-grade), both containing 0.1 % formic
acid, were used as the mobile phase. The following linear gradient was used: 10 %
acetonitrile for three min, up to 90 % acetonitrile within 20 min, hold for five minutes
and back to start conditions. The separation was performed on a Nucleodur C18 HD
Pyramid-column (250×4 mm, 5 μm, Macherey-Nagel) at a flow rate of 0.3 mL/min.
12
ACS Paragon Plus Environment

Page 13 of 31
Journal of Agricultural and Food Chemistry
259
260
Samples were dissolved in acetonitrile/water (1:1), diluted to appropriate
concentrations, 20 µL injected manually via a six port valve.
261
262
263
264
265
266
267
Structure-activity relationship. The compounds used in the olfactory analysis
were compared to the structure of the genuine pineapple impact aroma volatiles
(1,3E,5Z)-undecatriene and (1,3E,5Z,8Z)-undecatetraene. To identify the most
abundant molecular conformation of each compound, structures were energy-
minimized using the DREIDING force field. These data were used for Quenched
Dynamics Simulation (1 ns, 300 K) to obtain the most likely geometric spatial
conformation of the odor compounds.11
268
269
270
271
272
273
274
275
276
Nuclear magnetic resonance spectroscopy. Structure elucidation was
performed by 1H and 13C 1D-spectra with broadband decoupling as well as 2D-Spectra
13
like DQF-COSY for proton correlations and C-edited HSQC and HMBC spectra for
proton carbon correlations. All measurements were performed on a Bruker Ultrashield
1
500 MHz spectrometer with DRX-console and cryo TCI H, 13C/15N Probe with z-
gradients. For measurements the products were dissolved in 0.7 mL deuterated
trichloromethane and measured at 298.0 K. The residual solvent signal of
trichloromethane was used as internal standard. All data were evaluated by
MestReNova and Topspin software.
277 RESULTS AND DISCUSSION
278
279
280
281
282
283
Retrosynthesis of (5E/Z,7E,9)-decatrien-2ones. The retrosynthesis of the
target (5E/Z,7E,9)-decatrien-2-ones is shown in Figure 1. The decatrien-2-one
skeleton was built along a Wittig reaction of two C5 units, an aldehyde with a methyl
ketone group and a triphenylphosphonium salt bearing the conjugated pentadiene unit.
To avoid side reactions unprotected 4-ketopentanal was not reacted directly with the
respective Wittig salt. Thus, the keto group was converted to its acetal (3). Subsequent
13
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 14 of 31
284
285
a reductive acetal deprotection (DIBAL) was required after the Wittig reaction to yield
the targeted decatrien-2-ones (6a,b).
286
287
288
289
290
291
292
The triene moiety of the decatrien-2-one was introduced via the phosphonium
salt of (1,3E)-pentadiene which was generated by the nucleophilic substitution (SN1´)
of 1,4-pentadienol with hydrogen bromide. This reaction proceeds stereo-selectively
under formation of 1,3(E)-conjugated double bonds. The second C5-unit for the Wittig
reaction, aldehyde (4), providing the methyl ketone unit, was synthesized starting with
ethyl levulinate. The keto group was protected by acetal formation with ethylene glycol
and the ester subsequently reduced with DIBAL to give aldehyde (4).
293
294
295
296
297
298
299
300
301
302
303
Both C5-units were coupled in a Wittig reaction resulting the targeted C10-
skeleton and the third double bond in conjugation to the already present conjugated
diene system. In general the (E/Z) selectivity of the Wittig reaction depends on the
stabilization of the mesomeric ylide and ylene intermediates. Stabilization of the ylide
favors the formation of the (E)-isomer, whereas non-stabilized give the (Z)-isomer. In
case of preferred ylene formation in the transition state bulky substituents favor the
formation of the (Z)-isomer, whereas repellant electronegative groups the (E)-isomer.
Here, no preference for one of the 2-(5(E)-hepta-3,5-dien-1-yl)-2-methyl-1,3-dioxolane
isomers (5a,b, (E/Z) = 44:56; assignment by 1H-NMR) was found. Hence, after removal
of the protection group the targeted (5E/Z,7E,9)-decatrien-2-ones (6a,b) were obtained
with an almost equimolar isomeric distribution.
304
305
306
307
308
Separation of the two isomers succeeded via GC-MS analysis (CW20M: 1842
and 1863, respectively). However, an assignment to the respective 5(E/Z) on the basis
of the electron impact (EI) mass spectra was not possible. Re-evaluation of extracts
from the fungal culture supernatant at the day of maximum product concentration
(1.1 mg/L 5(E) isomer and 0.07 mg/L 5(Z) isomer; at day five) revealed the presence
14
ACS Paragon Plus Environment

Page 15 of 31
Journal of Agricultural and Food Chemistry
309
310
311
of both compounds. The mass spectra of the synthesized isomers were nearly identical
to each other and to the mass spectra of the pineapple flavor compounds found in
culture medium of the basidiomycete F. betulina.
312
313
314
315
316
317
318
319
320
321
322
Structure elucidation of (5E/Z,7E,9)-decatrien-2-ones. Both isomers were
clearly separated on GC-columns of different polarity, but the EI-mass spectra showed
no significant differences. Ionization at the carbonyl oxygen resulted in neutral losses
of m/z 15 (CH3) and m/z 43 (CH3C=O), indicative of the terminal methyl ketone group.
As soon as the conjugated triene moiety of the molecule becomes ionized,
fragmentation occurs preferentially after rearrangements. The intensity of the signals
at m/z 91/92 and 77/79 indicated the formation of stable cyclic ions as they are known
for cyclohexene derivatives, such as limonene. A similar behavior was observed while
analyzing polyenes, inter alia (1,3,5)-undecatriene. However, due to the ionization of
the conjugated triene system information about the stereochemistry of the double
bonds (5 and 7) was lost.
323
324
325
326
327
328
329
330
331
332
333
Accurate mass determination resulted 150.096 amu, corresponding to an empirical
formula of C10H14O (150.104 calc.). The pineapple-like smelling diastereomers were
identified as (5E/Z,7E/Z,9)-decatrien-2-ones, but the geometry of the 5 and 7 double
bonds remained unknown. Data on decatrien-2-ones are rare in literature. In 2010,
Nakanishi and Watanabe published a patent and Tomita a research article dealing with
an undecatrien-3-one (no exact structure given) identified in the Yuzu fruit (Citrus junos
Sieb. Ex Tanaka). This compound was claimed as an ingredient of fresh fruit-like
aroma compositions.12–14 Both authors presented (5,7,9)-decatrien-2-one as a fruity
flavor.13,14 Neither further publications nor spectral data were published so far
(SciFinder structural search, Sept. 08, 2019). Re-analysis of fresh pineapple, juices as
well as canned products via solvent extraction techniques as well as SBSE did not
15
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 16 of 31
334
335
indicate the presence of decatrienones (data not shown; 200 g of pineapple sample;
LOD: according to perceived threshold masses shown in table 1).
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
Preparative gas chromatography (GC) was used for the accumulation of one
pure isomer from pooled extracts of the fungal culture medium (as described
elsewhere).7 Purified product was subsequently subjected to NMR analysis. As both
isomers were present after synthesis and further preparative separation was not
1
undertaken, they were measured together. Thus the H-NMR gave a double set of
signals in the spectrum. For both isomers the proton at C5 showed 3J-couplings with
protons at C4 and C6 revealing a multiplet (doublet, triplet), which was confirmed by a
2D proton correlation spectrum (DQF-COSY). In general, coupling constants (3J) of E-
isomers are higher than those of Z-isomers due to the torsion angle of 180°. The
multiplet at 5.42 ppm (J = 10.09 Hz) was assigned to the 5(Z) and that at 5.69 ppm
(J = 14.76 Hz) to the 5(E)-isomer. Comparison of the intensity of both signals gave a
ratio of 44(E):56(Z), the same as was found with GC-MS. The stereochemistry of the
double bound at C7 could only be assigned for the 5(Z)-isomer via NMR. The coupling
constant (J = 15.0 Hz) reveals a 7(E) configuration. Because of overlapping signals for
the 5(E)-isomer, the stereochemistry of the double bond at C7 was not assigned by
NMR. According to the synthetic route based on the Wittig reaction the stereochemistry
at the C7 double bond was defined as trans and suggested that the 7(E)-isomer
dominated in the cell cultures. This is explained by an isomerization of the 5(Z)-isomer
to the thermodynamically more stable 5(E)-form during prolonged incubation at
elevated temperature (25 °C).
356
357
358
Figure 2 compares the mixed 1H-NMR of the synthesized decatrien-2-ones with
the spectrum of the pineapple-like impact compound isolated earlier from the culture
medium of F. betulina.7 The multiplet at 5.7 ppm, assigned to the proton at C5, in the
16
ACS Paragon Plus Environment

Page 17 of 31
Journal of Agricultural and Food Chemistry
359
360
spectrum of the isolated decatrien-2-one showed that the isomer found in the culture
medium of F. betulina was unequivocally (5E,7E,9)-decatrien-2-one.
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
Sensorial characterization of (5E/Z,7E,9)-decatrien-2-ones and structurally
related compounds. Structure related methyl ketones were synthesized along the
same route. One reactant of the Wittig reaction, the protected ketopentanal was kept
constant, whereas the counterpart was varied in chain length as well as number and
position of double bonds. The respective structures were confirmed with GC-MS and
1H and 13C-NMR analyses. A sensorial evaluation of all compounds synthesized and
the commercial 9-decen-2-one was undertaken using GC-O, and perception
thresholds were determined by AEDA. If a sufficient chromatographic separation of
certain (E/Z)-isomers was not achieved, the mixed impression of both isomers was
recorded (Table 1). In general, all flavor compounds were described as fruity. More
detailed descriptions resulted in a highly diverse set of attributes. 5,7-octadien-2-ones
(10a,b) not only reminded of vanilla, but were also described as soil-like and fruity.
Solely the isomers of (5E/Z,7E)-decatrien-2-one (6a,b) were clearly identified as
pineapple aroma by the majority of panelists (4 out of 5). The 5(Z) isomer required a
800fold lower mass for perception (0.028 ng) compared to the 5(E)-isomer with 22 ng.
The isomer dominating in the culture medium of F. betulina was the (5E,7E,9)-
decatrien-2-one with the higher perception threshold mass. However, the relatively low
threshold of the E-isomer together with its actual concentration were sufficient to
provoke the distinct pineapple flavor of the fungal cell culture. Besides the (5,7,9)-
decatrien-2-ones further chemosynthesized methyl ketones, such as dec-9-en-2-one
and 5,9-decadien-2-ones (7a,b), imparted a slight pineapple-like odor impression.
382
383
In order to get insight into structural requirements for a pineapple odor
impression a comparison of global energy minimized conformations (quenched
17
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 18 of 31
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
dynamics simulation, DREIDING force field,11) of the respective methyl ketones was
performed. The calculated conformations are shown in Figure 3 and compared to each
other and to (1,3E,5Z)-undecatriene, a long-known genuine character impact
compound of fresh pineapple with a low threshold of 7.7 ng/kg water.15 All compounds
characterized as typically pineapple-like (6a,b; 7a,b and 11) provided a curved
structure consisting of a skeleton of at least 10 carbon atoms with a terminal double
bond opposite to the methyl ketone terminus. Since no variation of the keto function
was done, its impact was not evaluated directly. However, (1,3E,5Z)-undecatriene and
(1,3E,5Z,8Z)-undecatetraene were described as important constituents of fresh
pineapple flavor.15,16 Their odor was described as fruity, pineapple-like for
undecatriene and fresh, citrus-like for undecatetraene.17 Both olefins do not possess a
ketone function, but an “L”-shaped conformation, which is more pronounced for the
(1,3E,5Z)-undecatriene (Figure 4). The data suggest that the keto group was not a
mandatory structural element to evoke the pineapple sensation. The pineapple-like
odor impression was lost, if the length of the carbon chain was shortened (9a-d, 10a,b).
Although compounds 9b, 9c and 10b show the same “L”-shaped conformation like
(5Z,7E,9)-decatrien-2-one (6b), and additionally 10b shows the same conjugated
pentadienyl system with a terminal double bond, the pineapple character of the flavor
was completely lost. Alteration of the double bond system (number, position and
stereochemical orientation) while maintaining the carbon skeleton led to an increase
of the thresholds (less intense) for all compounds compared to 6b, but the pineapple
impression remains with one exception. Unlike the others, 5-decen-2-one (8a,b) lacks
a terminal double bond, which seems to be an essential molecular feature to evoke a
pineapple-like flavor.
18
ACS Paragon Plus Environment

Page 19 of 31
Journal of Agricultural and Food Chemistry
408
409
410
411
412
Since a long time, hexanoic acid prop-2-enyl ester (“allyl caproate”), absent from
pineapple volatilome, has been used to imitate pineapple flavor.18,19 It shows a nine
carbon skeleton, a carbonyl (ester) function and a terminal double bond. Still in use to
round off citrus, peach, apricot and apple blossom perfume compositions, it lacks a
convincing pineapple note.
413
414
415
416
417
418
419
420
421
Fungal production of (5E/Z,7E,9)-decatrien-2-ones. It remains a matter of
speculation, why a higher fungus should synthesize these compounds. However, in
their natural habitats, wood-destructing fungi are exposed to many microbial and
animal enemies as well as to organisms spreading their spores. Thus, it is not
surprising that they interact with their highly populated environment through volatile
chemical signals.20 Like the pineapple constituents (1,3E,5Z)-undecatriene and
(1,3E,5Z,8Z)-undecatetraene, which are known to act as algal pheromones, the
(5E/Z,7E,9)-decatrien-2-ones with their highly similar three dimensional structure may
serve as signaling compounds in fungi.21
422
423
424
425
426
427
428
429
430
431
The biogenesis of the decatrienones is obscure. Although first detected in cell
cultures supplemented with cabbage cuttings in concentrations of 1.1 mg/L, a
particular precursor role of this nutrient is doubtful. Fatty acids may serve as precursor
molecule for the formation of methyl ketones along the -oxidation.22 Fruity
constituents of high structural similarity, such as undecatrien-3-one in Yuzu (Citrus
junos), may be formed along this pathway. An analogous origin of the decatrienones
of F. betulina would require an odd-numbered unsaturated fatty acid, as they in fact
occur in basidiomycetes. Supplementing labeled precursors will clarify this question.
Another aim of future research could to investigate in detail the interaction of the
decatrienones with human odorant receptor proteins.
432
19
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 20 of 31
433 ABBREVIATIONS USED
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
AEDA
BHT
DCM
DE
Aroma extract dilution analysis
Butylated hydroxyl toluene
Dichloromethane
Diethyl ether
DIBAL
DMF
FID
Diisobutyl aluminiumhydride
Dimethyl formamide
Flame ionization detector
Gas chromatography coupled with mass spectrometry
Hydrogen bromide
GC-MS
HBr
LOD
MeOH
NMR
ODP
p.a.
Limit of detection
Methanol
Nuclear magnetic resonance spectroscopy
Olfactory detection port
pro analysi
PE
Pentene/diethyl ether
Room temperature
RT
SBSE
Stir bar sorptive extraction
451
20
ACS Paragon Plus Environment

Page 21 of 31
Journal of Agricultural and Food Chemistry
452 Acknowlegement
453
454
455
We are grateful to the Lower Saxony Ministry of Science and Arts for support through
the research cluster ‘Bioeconomy 2.0: Innovation potentials of side-streams of food
processing’.
21
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 22 of 31
456 References
457
458
(1) Montero-Calderón, M.; Rojas-Graü, M. A. and Martín-Belloso O., Eds. Handbook of Fruit
and Vegetable Flavors. Pineapple (Ananas comosus [L.] Merril) Flavor, 1st ed.; Wiley, 2010.
459
460
(2) Belitz, H.-D.; Grosch, W.; Schieberle, P. Lehrbuch der Lebensmittelchemie, 6th ed.;
Springer: Berlin, Heidelberg, 2008.
461
462
463
464
(3) Steingass, C. B.; Carle, R.; Schmarr, H.-G. Ripening-dependent metabolic changes in the
volatiles of pineapple (Ananas comosus (L.) Merr.) fruit. I. Characterization of pineapple
aroma compounds by comprehensive two-dimensional gas chromatography-mass
spectrometry, Anal. Bioanal. Chem. 2015, 407, pp. 2591–2608.
465
466
467
(4) Takeoka, G.; Buttery, R. G.; Flath, R. A.; Teranishi, R.; Wheeler, E. L.; Wieczorek, R. L.;
Guentert, M. Volatile Constituents of Pineapple ( Ananas Comosus [L.] Merr.). In Flavor
Chemistry, pp. 223–237.
468
469
(5) Pino, J. A. Odour-active compounds in pineapple ( Ananas comosus [L.] Merril cv. Red
Spanish), Int. J. Food Sci. Tech. 2013, 48, pp. 564–570.
470
471
472
(6) Berger, R. G.; Drawert, F.; Kollmannsberger, H.; Nitz, S.; Schraufstetter, B. Novel
volatiles in pineapple fruit and their sensory properties, J. Agric. Food Chem. 1985, 33,
pp. 232–235.
473
474
475
(7) Schimanski, S.; Krings, U.; Berger, R. G. From cabbage cuttings to pineapple flavor:
Ready to use flavors from side streams of the food industry. In Proceeding of Wartburg
Symposium on Flavor Chemistry and Biology, pp. 426–429.
476
477
(8) Miyazawa, N.; Nakanishi, A.; Tomita, N.; Ohkubo, Y.; Maeda, T.; Fujita, A. Novel key
aroma components of galbanum oil, J. Agric. Food Chem. 2009, 57, pp. 1433–1439.
478
479
(9) Ogura, T.; Usuki, T. Total synthesis of acerogenins E, G and K, and centrolobol,
Tetrahedron. 2013, 69, pp. 2807–2815.
22
ACS Paragon Plus Environment

Page 23 of 31
Journal of Agricultural and Food Chemistry
480
481
482
(10) van den Dool, H.; Dec. Kratz, P. A generalization of the retention index system including
linear temperature programmed gas—liquid partition chromatography, J. Chromatogr. A.
1963, 11, pp. 463–471.
483
484
(11) Mayo, S. L.; Olafson, B. D.; Goddard, W. A. DREIDING. A generic force field for
molecular simulations, J. Phys. Chem. 1990, 94, pp. 8897–8909.
485
486
487
(12) Miyazawa, N.; Tomita, N.; Kurobayashi, Y.; Nakanishi, A.; Ohkubo, Y.; Maeda, T.;
Fujita, A. Novel character impact compounds in Yuzu (Citrus junos Sieb. ex Tanaka) peel oil,
J. Agric. Food Chem. 2009, 57, pp. 1990–1996.
488
489
(13) Nakanishi, K.; Watanabe, H. Fragrant enone compounds having natural, fresh fruit-like
aroma and perfume/flavor compositions containing them, Jpn Kokai Tokkyo Koho. 2010.
490
491
(14) Tomita, N. Identification of YUZUNONE and evaluation of its derivatives, Nippon
Koryo Kyokai. 2010, pp. 69–76.
492
493
(15) Berger, R. G.; Kollmannsberger, H. Pineapple Flavours - Biosynthetic routes and
sensorial pro-perties. In Proceeding of Topics in Flavor Research, pp. 305–320.
494
495
496
(16) Tokitomo, Y.; Seinhaus, M.; Büttner, A.; Schieberle, P. Odor-Active Constituents in
Fresh Pineapple ( Ananas comosus [L.] Merr.) by Quantitative and Sensory Evaluation,
Biosci., Biotechnol., Biochem. 2014, 69, pp. 1323–1330.
497
498
(17) Neiens, S. D.; Steinhaus, M. Odor-Active Compounds in the Special Flavor Hops Huell
Melon and Polaris, J. Agric. Food Chem. 2018, 66, pp. 1452–1460.
499
500
(18) Ara, V.; Heil, M. Authentizität von Ananasaroma – Eine Betrachtung der Ester,
Flüssiges Obst. 2006, pp. 245–249.
501
(19) Dravnieks, A. Atlas of odor character profiles; ASTM: Philadelphia, Pa., 1985.
502
503
(20) Orban, A.; Fraatz, M. A.; Rühl, M. Aroma Profile Analyses of Filamentous Fungi
Cultivated on Solid Substrates, Adv. Biochem. Eng. Biotechnol. 2019, pp. 85–107.
23
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 24 of 31
504
505
(21) Boland, W.; Mertes, K. Biosynthesis of algal pheromones. A model study with the
composite Senecio isatideus, Eur. J. Biochem. 1985, 147, pp. 83–91.
506
507
(22) Kinderlerer, J. L. Fungal strategies for detoxification of medium chain fatty acids, Int.
Biodeter. Biodegr. 1993, 32, pp. 213–224.
508
24
ACS Paragon Plus Environment

Page 25 of 31
Journal of Agricultural and Food Chemistry
509 FIGURE CAPTIONS
510
511
512
Figure 1: Retrosynthesis of (5E/Z,7E,9)-decatrien-2-one and structurally related methyl
ketones (numbering corresponds to Table 1; * = commercial product; ° number of the
respective final product)
1
513
514
515
516
Figure 2: Comparison of H-NMR spectra of synthesized isomeric mixture of
(5E/Z,7E,9)-decatrien-2-one 6a, 6b (top) and isolated (5E,7E,9)-decatrien-2-one 6a
from F. betulina (bottom). Signals in frames correspond to the respective proton(s) at
C5.
517
518
519
Figure 3: Energy minimized structures of methyl ketones prepared (numbering
corresponds to Table 1). Bold red numbers indicate compounds with a pineapple-like
flavor sensation (quenched dynamics simulation. DREIDING force field.11)
520
521
522
Figure 4: Comparison of (5Z,7E,9)-decatrien-2-one (6b) with 1.(3E,5Z)-undecatriene
(12) and 1.(3E,5Z,8Z)-undecatetraene (13). Energy minimized structures (quenched
dynamics simulation. DREIDING force field.11)
523
25
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 26 of 31
Table 1: Odor impressions and perceived threshold masses of (5E/Z,7E,9)-decatrien-
2-one and structurally related compounds
mT [ng] Odor impression
O
10a.b
8a.b
12
5,0
0,5
5,0
Vanilla, soil like, fruity
O
O
Grapefruit, mandarin, orange, fruity, green
Pineapple (fermented), rubber, plastic,
bitter, fruity
Pineapple, bitter lemon, flowers, grassy,
fruity
O
7a.b
5,0
O
9b
9a
23
Citrus fruits, linalool, fruity, green,
Citrus fruits
O
18,5
O
0,195 Mandarin, fruity
9c
9d
O
5,0
Citrus fruits, flowers, fruity
O
O
6b
6a
0,028 Pineapple, fresh breath
22
Pineapple, fruity, pungent
mT = threshold of perceived mass injected on-column and still perceived at the GC-sniff-port
(median of five panellists)
26
ACS Paragon Plus Environment

Page 27 of 31
Journal of Agricultural and Food Chemistry
R2-6
R1
O
O
BrPh3P
2
( )
6a,b
(
)
4
( )
O
O
Br
O
O
1
( )
(7a,b)°
(8a,b)°
*R2
*R3
BrPh3P
BrPh3P
OEt
OH
Br
3
( )
O
O
(9a,b)°
(9c,d)°
O
R4
BrPh3P
OEt
R5
BrPh3P
BrPh3P
(10a,b)°
*R6
Figure 1
27
ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry
Page 28 of 31
Figure 2
28
ACS Paragon Plus Environment

Page 29 of 31
Journal of Agricultural and Food Chemistry
Figure 3
29
ACS Paragon Plus Environment