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Erucic acid

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Erucic acid
Names
IUPAC name
(Z)-Docos-13-enoic acid
Other names
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.647 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C22H42O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20-21-22(23)24/h9-10H,2-8,11-21H2,1H3,(H,23,24)/b10-9- checkY
    Key: DPUOLQHDNGRHBS-KTKRTIGZSA-N checkY
  • InChI=1/C22H42O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18-19-20-21-22(23)24/h9-10H,2-8,11-21H2,1H3,(H,23,24)/b10-9-
    Key: DPUOLQHDNGRHBS-KTKRTIGZBD
  • O=C(O)CCCCCCCCCCC\C=C/CCCCCCCC
Properties
C22H42O2
Molar mass 338.576 g·mol−1
Appearance White waxy solid
Density 0.860 g/cm3
Melting point 33.8 °C (92.8 °F; 306.9 K)
Boiling point 381.5 °C (718.7 °F; 654.6 K) (decomposes)
Insoluble
Solubility in methanol and ethanol Soluble
Hazards
Flash point 349.9 °C (661.8 °F; 623.0 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Erucic acid is a monounsaturated omega-9 fatty acid, denoted 22:1ω9. It has the chemical formula CH3(CH2)7CH=CH(CH2)11COOH. It is prevalent in wallflower seed with a reported content of 20 to 54% in high erucic acid rapeseed oil,[1] and 42% in mustard oil. Erucic acid is also known as cis-13-docosenoic acid and the trans isomer is known as brassidic acid.

Uses

Erucic acid has many of the same uses as mineral oils, but it is more readily biodegradable than some. It has limited ability to polymerize and dry for use in oil paints. Like other fatty acids, it can be converted into surfactants or lubricants, and can be used as a precursor to biodiesel fuel.

Derivatives of erucic acid have many further uses, such as behenyl alcohol (CH3(CH2)21OH), a pour point depressant (enabling liquids to flow at a lower temperature), and silver behenate, for use in photography.[2]

Sources of erucic acid

The seed oil of the rape plant is rich in erucic acid.

The name 'erucic' means: of or pertaining to Eruca; which is a genus of flowering plants in the family Brassicaceae. It is also the Latin for colewort, which today is better known as arugula.

Erucic acid is produced naturally (together with other fatty acids) across a great range of green plants, but especially so in members of the genus Brassica. For industrial purposes and production of erucic acid, rapeseed is used; for food purposes a 'low-erucic acid rapeseed' (LEAR) has been developed (canola), which contains fats derived from oleic acid instead of erucic acid.[3]

Biochemistry

Further information: Lipid metabolism

Erucic acid is produced by elongation of oleic acid via oleoyl-coenzyme A and malonyl-CoA.[4] Erucic acid is broken down into shorter-chain fatty acids in the human liver by the long-chain acyl CoA dehydrogenase enzyme.

Health effects

Studies done on laboratory animals in the early 1970s[5] show that erucic acid appears to have toxic effects on the heart at high enough doses. An association between the consumption of rapeseed oil and increased myocardial lipidosis, or heart disease, has not been established for humans.[6] While there are reports of toxicity from long-term use of Lorenzo's oil (which contains erucic acid and other ingredients), there are no reports of harm to people from dietary consumption of erucic acid.[7]: 646–657 

Publication of animal studies with erucic acid through the 1970s led to governments worldwide moving away from oils with high levels of erucic acid,[5] and tolerance levels for human exposure to erucic acid have been established based on the animal studies.[6][8][9]

In 2003, Food Standards Australia set a provisional tolerable daily intake (PTDI) for an average adult of about 500 mg/day of erucic acid, extrapolated based on "the level that is associated with increased myocardial lipidosis in nursing pigs."[6] "There is a 120-fold safety margin between this level and the level that is associated with increased myocardial lipidosis in nursing pigs. The dietary exposure assessment has concluded that the majority of exposure to erucic acid by the general population would come from the consumption of canola oil. The dietary intake of erucic acid by an individual consuming at the average level is well below the PTDI, therefore, there is no cause for concern in terms of public health and safety. However, the individual consuming at a high level has the potential to approach the PTDI. This would be particularly so if the level of erucic acid in canola oil were to exceed 2% of the total fatty acids."[6]

Food-grade rapeseed oil (also known as canola oil, rapeseed 00 oil, low erucic acid rapeseed oil, LEAR oil, and rapeseed canola-equivalent oil) is regulated to a maximum of 2% erucic acid by weight in the USA[8] and 5% in the EU,[9] with special regulations for infant food.

References

  1. ^ Sahasrabudhe, M. R. (1977). "Crismer values and erucic acid contents of rapeseed oils". Journal of the American Oil Chemists' Society. 54 (8): 323–324. doi:10.1007/BF02672436.
  2. ^ Economic Research Service, USDA (1996). "Crambe, Industrial Rapeseed, and Tung Provide Valuable Oils" (PDF). Fats and Oils, Industrial Uses: 18. Archived from the original (pdf) on 10 October 2006. {{cite journal}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  3. ^ David J. Anneken, Sabine Both, Ralf Christoph, Georg Fieg, Udo Steinberner, Alfred Westfechtel "Fatty Acids" in Ullmann's Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim. doi:10.1002/14356007.a10_245.pub2
  4. ^ Bao Xiaoming; Pollard Mike; Ohlrogge John (1998). "The Biosynthesis of Erucic Acid in Developing Embryos of Brassica rapa". Plant Physiol. 118 (1): 183–190. doi:10.1104/pp.118.1.183. PMC 34854. PMID 9733537.
  5. ^ a b Amy McInnis, 21 May 2004 The Transformation of Rapeseed Into Canola: A Cinderella Story
  6. ^ a b c d Food Standards Australia New Zealand (June 2003) Erucic acid in food: A Toxicological Review and Risk Assessment Technical report series No. 21; Page 4 paragraph 1; ISBN 0-642-34526-0, ISSN 1448-3017
  7. ^ Luger CL et al. Food Safety and Foodborne Toxicants. Chapter 14 in Hayes' Principles and Methods of Toxicology, Sixth Edition. Eds A. Wallace Hayes, Claire L. Kruger. CRC Press, 2014 ISBN 9781842145371. Quote: "In humans. however. although the long-term use of Lorenzo's oil (oleic acid and erucic acid) in the treatment of adrenoleukodystrophy or adrenomyeloneuropathy leads to thrombocytopenia and lymphopenia (Unkrig et al. 1994), adverse effects from dietary consumption of erucic acid have not been reported."
  8. ^ a b U.S. Dept. of Health and Human Services, CFR - Code of Federal Regulations Title 21 1 April 2010.
  9. ^ a b The Commission of the European Communities (1980). "Commission Directive 80/891/EEC of 25 July 1980 relating to the Community method of analysis for determining the erucic acid content in oils and fats intended to be used as such for human consumption and foodstuffs containing added oils or fats". EurLex Official Journal. 254.
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