Erucic acid

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Erucic acid
Erucic acid.png
Identifiers
CAS number 112-86-7 YesY
PubChem 5281116
ChemSpider 4444561 YesY
UNII 075441GMF2 YesY
KEGG C08316 YesY
ChEBI CHEBI:28792 YesY
ChEMBL CHEMBL1173380 YesY
Jmol-3D images Image 1
Properties
Molecular formula C22H42O2
Molar mass 338.57 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 (decomposes)
Solubility in water Insoluble
Solubility in methanol and ethanol Soluble
Hazards
Flash point 349.9 °C (661.8 °F; 623.0 K)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Erucic acid is a monounsaturated omega-9 fatty acid, denoted 22:1ω9. It has the 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[edit]

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 bio-diesel 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[edit]

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 kale.

Erucic acid is produced naturally (together with other fatty acids) across a great range of green plants, but especially so in members of the brassica family. For industrial purposes, a Low-Erucic Acid Rapeseed (LEAR) has been developed, which contains fats derived from oleic acid instead of erucic acid.[3]

Biochemistry[edit]

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[edit]

No negative health effects of any exposure to erucic acid have been documented in humans.[5]

However, based on studies done on laboratory animals in the early 1970s,[6] erucic acid appears to have toxic effects on the heart at high enough doses.[5]

Publication of animal studies with erucic acid through the 1970s led to governments worldwide moving away from oils with high levels of erucic acid,[6] and tolerance levels for human exposure to erucic acid have been established based on the animal studies.[5][7][8]

In 2003 Food Standards Australia set a Provisional Tolerable Daily Intake (PTDI) of about 500 mg/day of erucic acid, based on "the level that is associated with increased myocardial lipidosis in nursling pigs."[5] "There is a 120-fold safety margin between this level and the level that is associated with increased myocardial lipidosis in nursling 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 was to exceed 2% of the total fatty acids."[5]

Low erucic acid rapeseed[edit]

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.[7] and 5% in the EU,[8] with special regulations for infant food.

References[edit]

  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. 
  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 c d e 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
  6. ^ a b Amy McInnis, May 21, 2004 The Transformation of Rapeseed Into Canola: A Cinderella Story
  7. ^ a b U.S. Dept. of Health and Human Services, CFR - Code of Federal Regulations Title 21 1 April 2010.
  8. ^ 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. 

External links[edit]