Thiyl radical-catalyzed isomerization of oils: An entry to the trans lipid library


The unsaturated fatty acyl moieties of TAG present in natural oils of borage, olive, and rice were converted to their corresponding geometrical trans isomers by thiyl radical-catalyzed isomerization. Thiyl radicals were generated from 2-mercaptoethanol under photolytic or thermal conditions. A relevant feature of this method is the absence of double-bond shifts, so that no positional trans isomers or conjugated polyenes are formed. Oils obtained after the isomerization were winterized to further increase their trans fatty acid content. Methanolysis and hydrolysis of the trans oil mixtures using an enzymatic method (lipase B from Candida antarctica) gave good conversions to the corresponding trans FAME and fatty acids, respectively. These results are relevant for the studies of lipid isomerism and trans fatty acid recognition, which is a growing concern in biochemistry and nutrition, and open new perspectives for the synthesis of glycerides and studies of their structure-activity relationships.

This is a preview of subscription content, log in to check access.


  1. 1.

    Aro, A., Epidemiological Studies of trans Fatty Acids and Coronary Heart Disease, in Trans Fatty Acids in Human Nutrition, edited by J.L. Sébédio and W.W. Christie, The Oily Press, Dundee, 1998, pp. 235–260.

    Google Scholar 

  2. 2.

    McDonald, R.E., and M.M. Mossoba, Methods for trans Fatty Acid Analysis, in Food Lipids: Chemistry, Nutrition and Biotechnology, edited by C.C. Akoh and D.B. Min, Marcel Dekker, New York, 2002, pp. 169–204.

    Google Scholar 

  3. 3.

    Lie Ken Jie, M.S.F., and C.C. Lam, 1H-Nuclear Magnetic Resonance Spectroscopic Studies of Saturated, Acetylenic and Ethylenic Triacylglycerols, Chem. Phys. Lipids 77:155–171 (1995).

    CAS  Article  Google Scholar 

  4. 4.

    Lie Ken Jie, M.S.F., and J. Mustafa, High-Resolution Nuclear Magnetic Resonance Spectroscopy—Applications to Fatty Acids and Triacylglycerols, Lipids 32:1019–1035 (1997).

    Article  Google Scholar 

  5. 5.

    Sgoutas, D.S., and F.A. Kummerow, Cis-trans Isomerization of Unsaturated Fatty Acid Methyl Esters Without Double Bond Migration, 4:283–287 (1969).

    CAS  Article  Google Scholar 

  6. 6.

    Ferreri, C., C. Costantino, L. Perrotta, L. Landi, Q.G. Mulazzani, and C. Chatgilialoglu, Cis-trans Isomerization of Polyunsaturated Fatty Acid Residues in Phospholipids Catalyzed by Thiyl Radicals, J. Am. Chem. Soc. 123:4459–4468 (2001).

    CAS  Article  Google Scholar 

  7. 7.

    Ferreri, C., A. Samadi, F. Sassatelli, L. Landi, and C. Chatgilialoglu, Regioselective cis-trans Isomerization of Arachidonic Double Bonds by Thiyl Radicals: The Influence of Phospholipid Supramolecular Organization, 126:1063–1072 (2004).

    CAS  Article  Google Scholar 

  8. 8.

    Ferreri, C., M.R. Faraone-Mennella, C. Formisano, L. Landi, and C. Chatgilialoglu, Arachidonate Geometrical Isomers Generated by Thiyl Radicals: The Relationship with trans Lipids Detected in Biological Samples, Free Radic. Biol. Med. 33:1516–1526 (2002).

    CAS  Article  Google Scholar 

  9. 9.

    Shimada, Y., Y. Watanabe, T. Samukawa, A. Sugihara, H. Noda, H. Fukuda, and A. Tominaga, Conversion of Vegetable Oil to Biodiesel Using Immobilized Candida antarctica Lipase, J. Am. Oil Chem. Soc. 76:789–793 (1999).

    CAS  Google Scholar 

  10. 10.

    Borgdorf, R., and S. Warwel, Substrate Selectivity of Various Lipases in the Esterification of cis- and trans-9-Octadecenoic Acid, Appl. Microb. Biotechnol. 51:480–485 (1999).

    CAS  Article  Google Scholar 

  11. 11.

    Jaworski, J., and E.B. Cahoon, Industrial Oils from Transgenic Plants, Curr. Opin. Plant Biol. 6:178–184 (2003).

    CAS  Article  Google Scholar 

  12. 12.

    Grandgirard, A., A. Piconneaux, J.L. Sébédio, and F. Julliard, Trans Isomers of Long-Chain n−3 Polyunsaturated Fatty Acids in Tissue Lipid Classes of Rats Fed with Heated Linseed Oil, Reprod. Nutr. Dev. 38:17–29 (1998).

    CAS  Google Scholar 

  13. 13.

    Huang, X., and C. Fang, Dietary trans Fatty Acids Increase Hepatic Acyl-CoA: Cholesterol Acyltransferase Activity in Hamsters, Nutr. Res. 20:547–558 (2000).

    CAS  Article  Google Scholar 

  14. 14.

    Kramer, J.K.C., V. Fellner, M.E.R. Dugan, F.D. Sauer, M.M. Mossoba, and M.P. Yurawecz, Evaluating Acid and Base Catalysis in the Methylation of Milk and Rumen Fatty Acids with Special Emphasis on Conjugated Dienes and Total trans Fatty Acids, Lipids 32:1219–1228 (1997).

    CAS  Article  Google Scholar 

  15. 15.

    Wolff, R.I., and D. Precht, A Critique of 50-m CP-Sil 88 Capillary Columns Used Alone to Assess trans-Unsaturated FA in Foods: The Case of the TRANSFAIR Study, 37:627–629 (2002).

    CAS  Article  Google Scholar 

  16. 16.

    Official Methods and Recommended Practices of the AOCS, edited by D. Firestone, 5th edn., AOCS Press, Champaign, 1998.

    Google Scholar 

  17. 17.

    Chatgilialoglu, C., C. Ferreri, M. Ballestri, Q.G. Mulazzani, and L. Landi, Cis-trans Isomerization of Monounsaturated Fatty Acid Residues in Phospholipids by Thiyl Radicals, J. Am. Chem. Soc. 122:4593–4601 (2000).

    CAS  Article  Google Scholar 

  18. 18.

    Chatgilialoglu, C., A. Altieri, and H. Fischer, The Kinetics of Thiyl-Radical Induced Reactions of Monounsaturated Fatty Acid Esters, 124:12816–12823 (2002).

    CAS  Article  Google Scholar 

  19. 19.

    Loliger, J., P. Lambelet, R. Aeschbach, and E. Prior, Natural Antioxidants: From Radical Mechanisms to Food Stabilization, in Food Lipids and Health, edited by R.E. McDonald and D.B. Min, Marcel Dekker, New York, 1996, pp. 68–77.

    Google Scholar 

  20. 20.

    Chatgilialoglu, C., L. Zambonin, A. Altieri C. Ferreri, Q.G. Mulazzani, and L. Landi, Geometrical Isomerism of Monounsaturated Fatty Acids. Thiyl Radical Catalysis and Influence of Antioxidant Vitamins, Free Radic. Biol. Med. 33:1143–1147 (2002).

    Article  Google Scholar 

  21. 21.

    Warwel, S., R. Borgdorf, and L. Brühl, Substrate Selectivity of Lipases in the Esterification of Oleic Acid, Linoleic Acid, Linolenic Acid and Their All-trans-Isomers and in the Transesterification of cis/trans-Isomers of Linoleic Acid Methyl Ester, Biotechnol. Lett. 21:431–436 (1999).

    CAS  Article  Google Scholar 

Download references

Author information



Corresponding authors

Correspondence to Carla Ferreri or Chryssostomos Chatgilialoglu.

About this article

Cite this article

Samadi, A., Andreu, I., Ferreri, C. et al. Thiyl radical-catalyzed isomerization of oils: An entry to the trans lipid library. J Amer Oil Chem Soc 81, 753–758 (2004).

Download citation

Key Words

  • Geometrical isomerization
  • lipase
  • thiyl radicals
  • trans fatty acids
  • trans oils