gaims
It
Wee,. •
FISHERIES AND MARINE SERVICE
Translation Series No. 3914
Autoxidation behavior of tritetradecyl glycerol ether by comparison
with glyceryl trimyristate (trimyristin) and coconut oil
by V. Miller
•
Original title: Autoxidationsverhalten von TritetradecylglycerinNther im Vergleich
zu Trimyristin und Kokosa
From: Fette Seifen Anstichm. 78(10): 412-414, 1976
Translated by the Translation Bureau e MA)
Multilingual Services Division
Department of the Secretary of State of Canada
Department of the Environment
Fisheries and Marine Service
Halifax Laboratory
Halifax, N.S.
1977
8 pages typescript
I^a vh H-391 L1I!ff
DEPARTMENT OF THE SECRETARY OF STATE
SECRÉTARIAT D'ÉTAT
TRANSLATION BUREAU
BUREAU DES TRADUCTIONS
MULTILINGUAL SERVICES
DIVISION DES SERVICES
CANADA
DIVISION
MULTILINGUES
TRANSLATED FROM - TRADUCTION DE
INTO - EN
German
English
AUTHOR - AUTEUR
Müller, V.
TITLE IN ENGLISH - TITRE ANGLAIS
Autoxidation behavior of tritetradecyl glycerol ether by comparison
with glyceryl trimyristate (trimyristin) and coconut oil
TITLE IN FOREIGN LANGUAGE (TRANSLITERATE FOREIGN CHARACTERS)
TITRE EN LANGUE ÉTRANGÉRE (TRANSCRIRE EN CARACTÈRES ROMAINS)
Autoxidationsverhalten von Tritetradecylglycerinâther im Vergleich zu
Trimyristin und Kokosdl.
REFERENCE IN FOREIGN LANGUAGE (NAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE,FOREIGN CHARACTERS.
REFÉRENCE EN LANGUE ^TRANGERE (NOM DU LIVRE OU PUBLICATION).,4U COMPLET, TRANSCRIRE EN CARACTÈRES ROMAINS.
Fette-Seifen-Anstrichmittel
REFERENCE IN ENGLISH - RÉFÉRENCE EN ANGLAIS
Fats - Soaps - Paints
PUBLISHER- ÉDITEUR
DATE OF PUBLICATION
DATE DE PUBLICATION
not given
YEAR
ANNEE
PLACE OF PUBLICATION
LIEU DE PUBLICATION
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VOLUME
1976
ISSUE N0.
NUMÉRO
10
PAGE NUMBERS IN ORIGINAL
NUMEROS DES PAGES DANS
L'ORIGINAL
412-414
NUMBER OF TYPED PAGES
NOMBRE DE PAGES
DACTYLOGRAPHIÉES
8
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(A
fl
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0d cl-1
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December
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1101585
3
1976
UNrDÎ1 i.;l.j Tiâr cN1.RAÎION
For inf'c:-niin";on only
TRAi?:!C'i4o,? NON MEVISEF
Informa;-ion seulerrcnf
SOS-200-10-6 (RF V. 2/88)
7 630-21-029-6333
F4-rw 43W4
,
DEPARTMENT OF THE SECRETARY OF STATE
SECRÉTARIAT D'ÉTAT
TRANSLATION BUREAU
BUREAU DES TRADUCTIONS
MULTILINGUAL SERVICES
DIVISION DES SERVICES
4
DIVISION
CLIENT'S NO.
NO DU CLIENT
1101585
DEPARTMENT
MINISTERE
DIVISION/BRANCH
DIVISION/DIRECTION
Environment
BUREAU NO.
NO OU BUREAU
1101585
MULTILINGUES
CANADA
Fisheries
LANGUAGE
LANGUE
.
German
vt
Muller, V.:
CITY
VILLE
14 A-lC
TRANSLATOR(INITIA LS)
TRADUCTEUR ( INITIALES)
MM,A.
1977
Autoxidationsverhalten von Tritetradecylglycerinâther
im Vergleich zu Trimyristin und Kokosôl.
[Autoxidation behavior of tritetradecyl glycerol ether
by comparison with glyceryl trimyristate (trimyristin) and
coconut oil].
Fette-Seifen-Anstrichmittel Z8: #10, 412-414 (1976).
ABSTRACT
Tritetradecyl glycerol ether is consjderably less stable towards
atmospheric oxygen than glyceryl ^myristate and coconut oil:
During the storage of tritetradecyl glycerol ether at 600 C up
to 96 hours, the peroxide value. increases continuously after
an incubation time. Under the same conditions, the peroxide
value of a reference sample containing 500 ppm of a-tocopherol did not increase. Upon heating to 1800 C the tritetradecyl glycerol ether is degraded much more rapidly than glyceryl myristite and coconut oil. Chiefly polar reaction products are being formed, according to liquid and gel permeation
chromatography presumably mono- and dialkyl glycerol ethers,
tetradecanal, tetradecanol and further compounds not yet
identified. The reaction products, in part, possess a higher
molecular weight than the original compound. The resolution
of the reaction products by liquid chromatography is described.
From the Unilever Research Association, Hamburg
Author`s address: Dr. V. Müller, Unilever Forschungsgesellschaft mbH,
---------------- Behringstrasse 154
D2000 Hamburg50
WEST GERMANY
ElNM4,°;:4:y
a.F15{
TRADUCTION NON VZEil?SEF
l.mfor:wafjcan saarl:ÿt;ie*
SOS-200-10-31
7030-21•029•5332
t
2
1. INTRODUCTION
It has been proposed that trialkyl glycerol ether be used as
substitute for dietary fats to reduce thecaloric content of foodstuffs (1). Apart from that, such compounds may also become useful
as markers in clinical and diagnostic fat absorption studies (2-4).
We have investigated the autoxidative behavior of tritetradecyl
glycerol ether upon storage and under thermic stress in the presence
of air. Trymiristin (glyceryl trimyristate) and coconut oil were
used for comparison.
2. MATERIAL
Tritetradecyl glycerol ether (TTG) was prepared from tetradecyl
bromide and glycerol according to the method described in reference
#5. Part of the sample was deodorized at 180 °C at a water throughput of 60%. Peroxide values of the samples, according to Wheeler,
were 1.7 prior to deodorization and 1.3 after deodorization or 3.5
respectively after three months of dark storage of the deodorized
sample at 15 ° C under nitrogen.
The melting point of the sample crystallized from hexane (as
gleaned from TLC heating curves) amounted to 35.5 ° C, following solidification from the melt - 29.5 °C. The gas-chromatographically determined purity of the sample was 95.9%; for further details the reader
is referred to Table 2.
Coconut oil is the plant fat most closely resembling TTG with
respect to melting point, molecular weight and chain length. The
commercial product used showed a climbing melting point of 26 ° C and
- according to the results obtained by gel permeation chromatography
(GPC) - it contained 98.3% of triglycerides, of these 80.5% were medium chain triglycerides, corresponding to a molecular weight of approximately 680, and 17.8% long-chain triglycerides.
Trimyristin is equivalent to TTG in chain length. Due to esterfication, the molecular weight and the melting point (57.5 °C) are
considerably higher than they are in TTG. GPC revealed that the
sample used contained 96.8% of triglycerides and 1.5% of diglycerides
3. METHODS AND RESULTS
3.1
Experiments done for general orientation
Experiments for the purpose of general orientation on the autoxidation of tritetradecyl glycerol ethers were carried out with 1 g
samples with a surface of approximately 16 cm 2/g, By the end of
2
413
4 hrs. the following peroxide values were found: at 60 0 0 - 2,
at 100 °C - 59, at 150 ° C - 71; after 20 hrs. at 150 °C - 28. After
4 hrs.
150 ° C, GPC revealed that only 47% of unaltered tritetradecyl
glycerol ether was still present; most of the evolving reaction products were low molecular compounds. After 20 hrs./150 ° C the proportion of compounds whose molecular weight corresponds to oligomers
of the trialkoxylipid had increased substantially.
Storage at 60 ° C
Duplicate samples of 3 g of TTG, trimyristin or coconut oil
respectively were subjected to the "Schaal" test (6) and stored in
the drk at 60 °C for 4,8,16,24,48 and 96 hrs. in roller panel jars*
air access) - at a surface of approximately 1.3 cm 2/g. The (with
"Schaal" test was repeated three months later on heated TTG with or
**
without the addition of 500 ppm DL-a-tocopherol .
The course of autoxidation was checkèd on 1 g portions of each
sample by determining the peroxide value according to Wheeler (Table 1).
Thin layer chromatographic evaluation was done on ready made
414
silica gel plates of the Merck Company (0.25 mm). Solvent used:
petroleum ether/ether/glacial acetic acid (90/10/1)(v/v).
Plates
were stained with 10% phosphomolybdic acid in ethanol; subsequently
they were heated to 180 ° C.
In the steamed TTG samples the induction period amounted to
approximately 16 hrs. In TTG samples which had not been steamed the
peroxide value climbed constantly without any discernible induction
period. The peroxide value of the triglycerides used as reference
compound remained unchanged. Following addition of 500 ppm of DL-atocopherol to the TTG the peroxide value remained unalterably low
during a 96 hr. period of storage.
After 24 hrs. TLC of TTG without added tocopherol revealed polar
reaction products whose Rf-values were equivalent to those of ditetradecyl glycerol ether.
The slightly nutty flavor of TTG increased during storage; after
24 hrs. a 'green' foreign taste - presumably of tetradecanal - was
clearly discernible.
The TTG samples to which tocopherol had been added only underwent
3.2
*height 65 mm, external diameter 24-25 mm, internal diameter 22-23 mm,
Besser Co. - ** Merck Co. Arlicle #8283.
4
e
Table 1: Changes in peroxide values (in mEQ 0 9/kg) of
tritetradecyl blycerol ether, coconut oil and
trimyristin during storage at 60 0 C
Kokosiil
Trimyristin
0
0
3
3
3
3
3
3
0
0.5
1.5
Lagerung Tritetradecylglyceriniither
gedâmpft
bei 60° C ungemit
(h)
dâmpft
ohne
500 ppm
Tocopherol
0
4
8
16
24
48
,96
1.7
5.5
7
10.0
15.9
34.0
84.5
3.5
3.3
3.6
4.1
12.3
38.6
85.6
9 .7
3
3
* after 3 monIns storage of the steamed sample at 15 ° C in the dark.
Lagerung bei = storage at; ungedgmpft = unsteamed; gedgmpft = steamed;
ohne = without; mit = with.
(For Table 2 = see p.5)
Retentionszeit
Table 3:
Decomposition products of
tritetradecyl glycerol
ether after 0, 8 and 40 hrs.
at 180 0 C, determined by
liquid chromatographic separation.
Retentionszeit =
retention time;
Flechen-% = surface %
Vermutete Substanz =
presumed substance;
stark polare Verunreinigungen,
z.T. Untergrund =
strongly polar cnntaminats,
partly background.
0h
Flâchen-%
8h
40h
Verniutete Substanz
2.6- 2.7
0
0.3
2.9- 3.0
0
1.8
1.0
3.2
0
1.2
10.1
Di tetradecylâther
3.5
95.4
72.1
13.0
Tritetradecylglyceriniither
3.8
0
0
17.4
4.8
0
1
1
5.8 - 5.9
0
0.4
0.6
8.2- 8.5
0
0.1
0.5
9. 9
0
0.1
0
10.3- 10.5
0.2
0.2
0
11.6
0.8
14.9
32.7
1 9.1 - 12.3
1.1
0.7
3.4
0.1
13.4
0
3.0
11.7
14.9- 15.2
0
0.1
0.3
15.4 - 15.5
2.5
4.1
8.4
Tetradecanal
DitetradecyIglycerinâther
Tetradecanol
MonoalkylglycerinWher, stark polare
Verunreinig- ungen,
z. T. Untergrund
I
5
Table 2:
Changes in tritetradecyl glycerol ether, trimyristin
and coconut oil during storage at 1800C.
TritetradecylglycerinHther
nach
Di;mpfen
vor
Diimpfen
Kokos81
nach Dâmpfen Trimyristin
mit
u-Tocopherol
Belastungsdauer bei 1800 C (h)
0
40
0
8
8
0
8
0
8
9.9
6.5
1.7
3.9
0.5
7.1 ;.
40
°
GPC-Bereidre (11. °lo)
Dimere und Verbindungen
hSherer Molekulargewichte
S
0.4
6.3
IVlonomere Ausgangsverbindung(en) (Triglyceride
bzw TritetradecYgY
1 1 cerin-
ïfher)
99
71.3
99.7
76.5
81.5
96.8
92.9
0.3
10.8
9.5
1.5
2.9
2.8
2.5
Ditetradecylglycerindther bzw.
Diglyceride, Dialkyldther
bzw. Verbindungen
entsprechender Molekulargewichte
0.3
11.7
Sonstiges
0.3
10.7
9S.3'r:r * 851.7"
1.2
2.8
0.4
LC-Bereiche (Tl. °lo)
3.3
11.2
95.-1
72.1
13.0
95.0
83.5
64.3
4.6
24.6
75.8
5.0
16.5
35.7
unpolarer als Ausgang
Ausgangsverbindung
polarer als Ausgang
Aussehen
Sclnnelzpunkt (Tottoli) (OC)
Steigsclmielzpunkt (° C)
farblos gelb
30
braun
farblos gelb
30.5
25.5
gelb
farblos fahlgelb
57.5
farblos schwach
gelb
56.5
26
26
* Solvent tetrahydrofurane; ## solvent CH2CL2; ### see text.
vor = prior to; nach = after; D&mpfen = steaming; mit = with;
Kokos8l = coconut oil; Belastungsdauer bei....duration of stress
at....; Bereiche = ranges;
Dimere und Verbindungen h8herer Molekulargewichte= dimers and
Monomere Ausgangsverbindcom ounds with higher molecular weights;
ung^en) = monomeric initial compound(s) ; bzw. = respectively;^^ VVIkA
Verbindungen entsprechender Molekulargewichte = compounds with
corresponding molecular weights; Sonstiges = other;
unpolarer als Ausgang = more unpolar than initial (compound);
Ausgangsverbindung = initial compound; polarer als Ausgang =
more polar than initial (compound); Aussehen = appearance;
farblos = colorless; gelb = yellow; braun = brown; fahlgelb =
feeble yellow; schwach gelb = slightly yellow;
Schmelzpunkt = melting point; Steigschmelzpunkt = climbing melting
point.
'
6
a very minor change in taste.
3.3
Thermic oxidative stress at 180 ° C
3 g samples of TTG, trimyristin and coconut oil were stored
for 8, 16, 24 and 40 hrs. at 180 0 0 in the dark in rolling wall jars
allowing access to air. Subsequently they were cooled under a N2
atmosphere. A reference sample of TTG (8 hr. storage) containing
500 ppm of DL-a-tocopherol was used.
The molecular weight distribution of selected samples was determined by GPC according to the method described in reference #7.
For high pressure liquid chromatography (HP-LC), the substances
dissolved in CC14 , put on steel columns (4.5 x 300 mm) filled with
Lichrosob SI 60, granule size 5 gm, were separated with two successive
solvent gradients:
Solvent I = heptane: 0 014 = 32:68; II = heptane: water-saturated
CHC1 :dioxane = 19:77:4; III = water-saturated CHOI :ethanol =
3
3
75:25. LC separation of thermic-oxidative degradation products
of tritetradecyl glycerol ether has already been described and reported in reference #8.
LC determination of the unaltered triglycerides of coconut oil
was done according to the method described in reference #9.
As early as after 8 hrs. of storage at 180 ° C 23% of the steamed
and 28% of the unsteamed tritetradecyl glycerol ether were found
to be decomposed (Table 2). Reaction products were overwhelmingly
more polar compounds than TTG (LC - Table 3); GPC revealed that
more compounds with lower molecular weight than compounds with higher
molecular weight had evolved.
By the end of 40 hrs. 87% of the TTG had disintegrated (LC Table 3). The decomposition products, such as aldehyde, alcohol,
dialkyl ether, monoglycerol ether and dialkyl glycerol ether have
also been observed as secondary products in the synthesis of tritetradecyl glycerol ether (5). Adding DL-a-tocopherol only reduces
the decomposition of the alkoxylipid to an insignificant extent
(Table 2). In trimyristin and coconut oil the proportion of unaltered
triglycerides found fter 8 hrs. at 180 ° C had been reduced by 3.9%
and 8.6% respectively (Table 2). In coconut oil the medium chain
triglyceride moiety remained constant with 80.5%, while the proportion of long-chain triglycerides declined from 17.8% to 9.1%.
7
For the most part, the new compounds evolving were dimeric compounds.
4.
DISCUSSION
Both at 60°C and at 190°C the saturated tritetradecyl glycerol
èther is less stable to autoxidation than trimyristin or coconut
oil.
It may therefore be assumed that TTG will undergo more rapid
oxidative changes even under storage conditions normally encountered
by fat and fat products. Although the positive influence exerted
by tocopherol at 60°C suggests that an admixture of plant oils with
high tocopherol levels might reduce the rate of TTG oxidation to
some extent, the oxygen sensitivity of TTG at higher temperatures
is not very auspicious, and its technical use as a non-caloric exchange for frying fats, for example, does not seem to offer a
realistic advantage.
11
The author is indebted to Dr. K. Aitzetmûller and colleagues for
elaborating and carrying out the liquid chromatography, Dr. M.
Unbehend and colleagues for gel permeation chromatography, and
Mrs. M. Patzig for careful and conscientious collaboration.
Received August 19, 1976.
■
8
REFERENCES
H. K. Mangold in: Ether Lipids, Chemistry and Biology,
F. Snyder, Ed., Acad. Press, New York, London 1972, S.161.
2 F. Paltauf, F: Spener, Chem. Phys. Lipids
2, 168 [1968].
3 W. E. Carlson u. H. S. Bailey, Brit , J.
Nutrit. 28, 295 [1972].
I?. G. H. Morgan u. A. F. Hofmann, J. Lipid Res. 11, 223
1
[1970].
5
V. Muller, Publikation in Vorbereitung.
N. T. Joyner u. J. E. McIntyre, Oil and Soap 15, 184
[1938].
Straufi u. G. Billek,
Fette • Seifen • Anstrichmittel 75, 689 [1973].
8 K. Aitzetmiiller, J. Chromatogr. Sci. 13, 445 [1975].
D K. Aitzetniiiller u. G. Guhr, Fette • Scifen • Anstrichmittel
78, 83 [1976].
7
M. Unbehend, H. Scharmann,
Publikation in Vorbereitung = publication in preparation.