Erucic acid
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| General | |||||||||||||||||||
| Surname | Erucic acid | ||||||||||||||||||
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| Molecular formula | C 22 H 42 O 2 | ||||||||||||||||||
| Brief description |
white crystalline solid |
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| properties | |||||||||||||||||||
| Molar mass | 338.58 g mol −1 | ||||||||||||||||||
| Physical state |
firmly |
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| density |
0.86 g cm −3 (20 ° C) |
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| Melting point |
28-32 ° C ; 33.5 ° C |
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| boiling point |
358 ° C (533 hPa) |
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| solubility |
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| Refractive index |
1.4534 (45 ° C) |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C | |||||||||||||||||||
The erucic acid (also: erucic acid ) is an easy- unsaturated fatty acid , which in large quantities in the seeds of cruciferous (Brassicaceae), some old oilseed rape , rape and sea cabbages place. The proportion of old rapeseed oil varieties was higher than that of modern ones. It is also found in broccoli seed oil and mustard oil and comes in Seetier- and fish oils before.
Structure and properties
Erucic acid is a white, crystalline solid that melts at 33.5 ° C and boils at 358 ° C. With a density of 0.86 g / cm 3 , erucic acid is lighter than water, in which it is insoluble. It is soluble in alcohols such as methanol or ethanol .
The molecule, which consists of a chain of 22 carbon atoms , has exactly one double bond and is - like all fatty acids - a carboxylic acid . The trans - isomer of erucic acid is the brassidic .
use
Erucic acid is used in the production of emulsifiers , surfactants and other chemicals that are added to lubricants, for example. Your methyl ester, methyl erucate, is used as a reference substance for gas chromatography .
Lorenzo's oil , a mixture of glycerol trioleate and glycerol trierucate (the triglycerides of oleic acid and erucic acid), is said to reduce the formation of long-chain saturated fatty acids in the human body in the case of lipid metabolism disorders ( adrenoleukodystrophy , adrenomyeloneuropathy ) .
Biological importance
Erucic acid is broken down more poorly by the mitochondrial oxidation system than other fatty acids. Like other long-chain fatty acids, erucic acid presumably blocks some of the enzymes involved , so that other fatty acids are also broken down more slowly.
Since erucic acid is nutritionally problematic (pathological change in the heart muscle, fatty heart and causing growth retardation in animal experiments), rapeseed could not previously be used to produce edible oil ( rapeseed oil ). Only the breeding of low erucic acid rapeseed (0.1 to 1.5%) rape varieties, the so-called “0 and 00 rape” (also LEAR , low erucic acid rapeseed ), made this possible. The acid is also contained in mustard oil , which is still used in India today; there, consumption does not appear to be associated with negative health effects. However, there are now low-erucic acid mustards with an erucic acid content of 1.1%, which are safe as food.
Very high doses of erucic acid lead to fatty heart muscle. Heart damage is known in particular from experiments with rats, which presumably have a different lipid metabolism than pigs , primates and humans. However, there is no known connection between the consumption of rapeseed oil and heart damage in humans, so that the upper limit for the tolerable daily dose is estimated on the basis of animal experiments. It is 500 mg erucic acid per day for an adult. Even with frequent consumption of rapeseed oil, which can be advantageous due to the high proportion of unsaturated fatty acids, and rapeseed oil products, this dose is not achieved if the proportion of erucic acid in the fatty acids is less than 2%.
For foods with more than 5% fat content and for edible fats, edible oils and their mixtures that are sold to the consumer, the ordinance on the maximum content of erucic acid in foods of May 24, 1977 (Federal Law Gazette I 1977, p. 782) applies. These must not contain more than 5% erucic acid, based on the total fatty acid content.
proof
The detection and determination of the content of erucic acid is usually carried out by gas chromatography of the methyl ester; in addition, a separation of the unsaturated isomers with silver nitrate - thin layer chromatography carried out.
literature
- EFSA Panel on Contaminants in the Food Chain (CONTAM): Erucic acid in feed and food. In: EFSA Journal. Volume 14, Issue 11, 2016, e04593, doi : 10.2903 / j.efsa.2016.4593 (with table on the erucic acid content ).
Web links
Individual evidence
- ↑ a b c Georg Trier: Chemistry of plant substances. Borntraeger, 1924, p. 105.
- ↑ a b c d e f g Entry on erucic acid in the GESTIS substance database of the IFA , accessed on February 8, 2018(JavaScript required) .
- ↑ HM Rauen: Biochemical Pocket Book. Springer, 1956, ISBN 978-3-642-53241-2 (reprint), p. 162.
- ^ Burkhard Fugmann, Susanne Lang-Fugmann, Wolfgang Steglich: RÖMPP Encyclopedia Natural Products. Thieme, 2000, ISBN 3-13-117711-X , p. 214.
- ↑ a b c Entry on erucic acid. In: Römpp Online . Georg Thieme Verlag, accessed on June 20, 2014.
- ↑ 13-Docosenoic acid at PlantFA Database, accessed October 26, 2017.
- ↑ Jürgen Falbe, Manfred Regitz (Ed.): RÖMPP Lexikon Chemie. Volume 2: Cm – G , 10th edition, Thieme, 1997, ISBN 978-3-13-734710-1 .
- ↑ B. Breuer, T. Stuhlfauth, HP Fock: Separation of fatty acids or methyl esters including positional and geometric isomers by alumina thin-layer chromatography. In: Journal of Chromatographic Science . 25, 1987, pp. 302-306, PMID 3611285 .