Vaccenic acid (18 carbon atoms), from the Latin word vacca, meaning cow, was discovered by Bertram S.H. in 1928 and was the first demonstration of presence of “trans” isomers of fatty acids in ruminant fats.
It is a monounsaturated fatty acid (one trans double bond; shorthand nomenclature cannot be used to name trans fatty acids) member of the sub-group called long chain fatty acids (LCFA) (from 14 to 18 carbon atoms).
Molecular weight: 282.46136 g/mol
Molecular formula: C18H34O2
IUPAC name: (E)-octadec-11-enoic acid
CAS registry number: 693-72-1
In purified form its melting point is at 44 °C (111.2 °F; 317.15 K).
Food sources of vaccenic acid
It is the major trans fatty acid, present as glycerol ester, in ruminant fats, like ox and sheep fats, and in fats of dairy products.
It results from the bacterial hydrogenation of rumenic acid in the first stomach of ruminants. However, it is present in small proportion.
Akoh C.C. and Min D.B. “Food lipids: chemistry, nutrition, and biotechnology” 3th ed. 2008
Chow Ching K. “Fatty acids in foods and their health implication” 3th ed. 2008