Trans-11-octadecenoic acid

AMIDES, FATTY ACID] (Vol 2) trans-11-Octadecenoic acid [693-72-1]... 

Trans-11-octadecenoic acid (vaccenic) is formed as a by-product of biohydrogenation in the rumen, and thence finds its way into the tissues of ruminant animais, and via meat and dairy products into human tissues, in addition, frans-isomers are formed during industriai hydrogenation of fats and oiis, as in margarine manufacture. 

Jiang J, Bjoerk L, Fonden R, Emanuelson M (1996) Occurrence of conjugated cis-9, trans-11 octadecenoic acid in bovine nulk effects of feed and dietary regimen. J Dairy Sci 79 438 45... 

Trans fatty acids present in the diet arise from two origins. The first is from bacterial biohydrogenation in the forestomach of ruminants, which is the source of trans fatty acids present in mutton and beef fats. These are present at a concentration of 2-9% of bovine fat. Trans-11-octadecenoic acid is the main isomer produced although trans-9- and tra s-10-octadecenoic acid are also produced. Thus, trans fatty acids occur in nature and cannot be considered to be foreign substances. 

Figure 11.10 Structure of ds-octadecenoic and trans-octadecenoic add (an example o/cis-trans isomerism). The common name for trans-octadecenoic acid is elaidic acid it is one of the few naturally occurring trans fatty acids. The common name for c/s-octadecenoic acid is oleic acid. Note that the two hydrocarbon chains are separated by the double bond which prevents rotation of the position of the two chains. The structure of the trans fatty acid is biochemically unusual and therefore biochemically excluded. ...

Buchgraber, M. and Ulberth, F. 2001. Determination of trans octadecenoic acids by silver-ion chromatography-gas liquid chromatography An intercomparison of methods. AOAC International 84 1490-1498. 

Fatty acid composition. High temperature processes can cause formation of trans-acids, particularly of trans-octadecenoic acids. The levels are quite small, but can be detected by GC on suitable columns (BPX70, CpSil88, etc.). Of particular relevance is the fact that these, once formed,... 

Precht, D., Molkentin, J. 1996. Rapid analysis of the trans-octadecenoic acid in milk fat. hit. Dairy J., 6,791-809. 

Mahfouz, M.M., Valicenti, A.J., Holman, R.T. 1980. Desaturation of isomeric trans-octadecenoic acids by rat liver microsomes. Biochim. Biophys. Acta 618, 1-12. 

Piperova, L.S., Sampugna, J., Teter, B.B., Kalscheur, K.F., Yurawecz, M.P., Ku, Y., Morehouse, K.M., Erdman, R.A. 2002. Duodenal and milk trans octadecenoic acid and conjugated linoleic acid (CLA) isomers indicate that postabsorptive synthesis is the predominant source of cis-9-containing CLA in lactating dairy cows. J. Nutr. 132, 1235-1241. 

Selberg, K.T., Lowe, A.C., Staples, C.R., Luchini, N.D., Badinga, L. 2004. Production and metabolic responses of periparturient Holstein cows to dietary conjugated linoleic acid and trans-octadecenoic acids. 1. Dairy Sci. 87, 158-168. 

As is outlined in the following section, it is now apparent that endogenous synthesis of RA occurs in most, if not all, animal species. The classic studies of Mahfouz et al. (1980) and Pollard et al. (1980) showed independently that positional isomers of trans-octadecenoic acids are desaturated by the enzyme A-9 desaturase in rat liver microsomal systems. All tram monoenes, A-4 to A-13, except A-8, 9, and 10, were substrates, with products being trans-A-x, cis-9 dienes. The rate of A-9 desaturation increased as the trans bond was removed further from the A-9 position, so that trans-A-4 and A-13 monoenes were most rapidly desaturated (Mahfouz et al., 1980). The trans-5, cis-9 18 2 was isomerized rapidly to the cis, cis diene without changing bond positions tram-4, cis-9 18 2 was isomerized similarly, but at a slower rate (Mahfouz et al., 1980). Significant amounts of some of the cis/trans dienes were desaturated further at A-6, to yield cis, tram, cis trienes (Pollard et al., 1980). 

Kemp, P., Lander, D.J., and Gunstone, F.D. 1984a. The hydrogenation of some cis- and trans-octadecenoic acids to stearic acid by a rumen Fusocillns sp. Br. J. Nutr. 52, 165-170. 

Figure 3. Surface pressure vs. area per molecule for some trans-octadecenoic acid isomers at 25° C...

Infrared analysis for trans-octadecenoic acid is a standard method (Report of the Spectroscopy Committee, 1959). Good quantitative results for the trans-isomers are possible by infrared analyses, and such analyses are done routinely by many laboratories. Kauffman and Lee (1960) found good agreement between the infrared analysis and the gas-liquid partition chromatographic analysis of methyl elaidate in hydrogenated vegetable oil... 

These procedures have been extensively employed and the following examples (p. 288) are taken from the work of Gunstone and Ismail (1967) and Barve and Gunstone (1971) who prepared all the octa-decynoic acids and from them all the cis- and trans-octadecenoic acids and of Gilman and Holland (1974) who prepared all the Cio, Cn, C12, C13 and Ci4 monoynoic acids. 

Piperova, L.S., J. Sampugna, B.B. Teter, K.F. Kalscheur, M.P Yurawecz, Y. Ku, K.M. Morehouse, and R.A. Erdman. Duodenal and Milk Trans Octadecenoic Acid and Conjugated Linoleic Acid (CLA) Isomers Indicate that Postabsorptive Synthesis is the Predominant Source of Cw-9-Containing CLA in Lactating Dairy Cows. J. Nutr. 132 1235-1241 (2002). 

Griinari, J.M., D.A. Dwyer, M.A. McGuire, D.E. Bauman, D.L. Palmquist, and K.V.V. Nurmela. Trans-Octadecenoic Acids and MUk Fat Depression in Lactating Dairy Cows. 

Katz and Keeney (8) identified an array of trans octadecenoic acids in cows milk with the trans- - being the most abundant isomer and all the isomers from positions 4 to 16 being observed. Parodi (9) identified cis-9, 1-18 2 in milk fat... 

Some of these issues were recently addressed by Buchgraber and Ulberth (74) in an intercomparison study to determine the trans octadecenoic acid content of soybean oil (SBO), spiked SBO, partially hydrogenated sunflower oil (PHSO), and a blend of palm oil and PHSO samples. A total of 12 laboratories participated, with... 

The results in Table 6 were obtained when both the overall rates of chain elongation and the condensation reaction were measured with 16 0 CoA, 6,9-18 2 CoA and 6,9,12-18 3 CoA as substrates The 8-hydroxy acyl-CoA dehydrase reaction was assayed only with the CoA derivatives of DL-8-hydroxy-stearic acid (8-OH-18 0 CoA) and DL-8-hydroxy-8,11-eicosadienoic acid (8-OH-8,11-20 2 CoA). The 2-trans-enoyl-CoA reductase reaction was assayed with the CoA derivatives of 2-trans-octadecenoic acid (2 trans-18 1 CoA) and 2-trans-8,ll-eicosatrienoic acid (2-trans-8,11-20 3 CoA) All reactions were assayed with the microsomes from rats raised on both a chow diet and a fat-free diet. Both the rates of the condensation reaction and the overall chain elongation reaction were depressed when rats were fed a chow diet These depressed rates of conversion were more pronounced when 16 0 CoA was used as substrate than when 6,9-18 2 CoA or 6,9,12-18 3 CoA were used as substrates. These results support our N-ethylmaleimide inhibition studies and are consistent with the concept that rat liver microsomes contain at least two different condensing enzymes. One condensing enzyme would preferentially utilize saturated substrates while another would act on unsaturated substrates. 

Table 3.45 Relative representation of frans-octadecenoic fatty acids in margarine blends containing partially hydrogenated fats in comparison with cows milk fat (% of total trans-octadecenoic acids indicated are ranges of values and median values).

Parodi (1976) determined the distribution of double bonds in cis and trans octadecenoic fatty acids from milk fat and bovine adipose tissue. About 95% of the 18 1 is the cis-9 isomer. Parodi detected the cis-12, -13, and -14 isomers, fatty acids not observed by Hay and Morrison (1970). The 18 1 content of Australian butterfat has varied throughout the season from 17.3 to 24.9 M%, with isolated trans unsaturation from 4.3 to 7.6 M%,... 

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