trans-Polyunsaturated fatty acids in French edible rapeseed and soybean oils (original) (raw)

Abstract

The fatty acid compositions of rapeseed and soybean oils marketed in France have been determined by gas liquid chromatography on a fused-silica capillary column coated with a 100% cyanopropyl polysiloxane stationary phase. Under the operating conditions employed, methyl esters of linolenic acid geometrical isomers could be separated and quantitated easily without any other complementary technique. With only one exception, all samples under study (eight salad oils and five food samples) contain geometrical isomers of linolenic acid in measurable, although variable, amounts. Total_trans_-18:3 acids may account for up to 3% of total fatty acids. This value corresponds to a degree of isomerization (percentage of_trans_ isomers relative to total octadecatrienoic acids) of 30%. Examination of our data indicates that the distribution pattern of linolenic acid geometrical isomers does not depend on the degree of isomerization. The two main isomers always have the_c,c,t_ and the_t,c,c_ configurations. These isomers occur in the almost invariable relative proportions of 47.8±1.7% and 41.1±1.0%, respectively. The third mono-trans isomer is present in lower amounts−6.5±0.7%. The only di-trans isomer that can be quantitated with sufficient accuracy is the_t,c,t_ isomer (4.9±1.5%). Mono-trans isomers of linoleic acid are also present in these oils. However, their maximum percentages are lower than those determined for linolenic acid geometrical isomers. In the oils showing the highest degrees of isomerization,trans isomers of linoleic acid account for 0.5% (rapeseed oils) and 1% (soybean oils) of total fatty acids. Taking into account all data, it would appear that the probability of isomerization of linolenic acid is about 13–14 times that of linoleic acid.

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References

1. Wiederman, L., and D. Erickson,Inform 2:200 (1991).
   Google Scholar
2. Ackman, R.G., S.N. Hooper, and D.L. Hooper,J. Am. Oil Chem. Soc. 51:42 (1974).
   CAS Google Scholar
3. Devinat, G., L. Scamaroni, and M. Naudet,Rev. Fr. Corps Gras 27:283 (1980).
   CAS Google Scholar
4. Wolff, R.L., and J.-L. Sebedio,J. Am. Oil Chem. Soc. 68:719 (1991).
   CAS Google Scholar
5. Grandgirard, A., F. Julliard, J. Prevost, and J.-L. Sebedio, —Ibid. 64:1434 (1987).
   CAS Google Scholar
6. Wolff, R.L.,J. Chrom. Sci., in press (1992).
7. Morrison, W.R., and L.M. Smith,J. Lip. Res. 5:600 (1965).
   Google Scholar
8. Enig, M.G., P. Budowski, and S.H. Blondheim,Hum. Nutr: Clin. Nutr. 38C:223 (1984).
   CAS Google Scholar
9. Grandgirard, A., J.-L. Sébédio, and J. Fleury,J. Am. Oil Chem. Soc. 61:1563 (1984).
   CAS Google Scholar
10. Grandgirard, A., and F. Julliard,Rev. Fr. Corps Gras, 34:213 (1987).
    CAS Google Scholar
11. Ratnayake, W.M.N., and J.L. Beare-Rogers,J. Chromatog. Sci. 28:633 (1990).
    CAS Google Scholar
12. Ratnayake, W.M.N., R. Hollywood, E. O'Grady, and J.L. Beare-Rogers,J. Am. Oil Chem. Soc. 67:804 (1990).
    CAS Google Scholar
13. McDonald, R.E., D.J. Armstrong, and G.P. Kreishman,J. Agric. Food Chem. 37:637 (1989).
    Article CAS Google Scholar
14. Mossoba, M.G., R.E. McDonald, J.-Y.T. Chen, D.J. Armstrong and S.W. Page, —Ibid. 38:695 (1990).
    Article Google Scholar
15. Mossoba, M.G., R.E. McDonald, D.J. Armstrong, and S.W. Page, —Ibid. 39:695 (1991).
    Article CAS Google Scholar
16. Perkins, E.G., and C. Smick,J. Am. Oil Chem. Soc. 64:1150 (1987).
    CAS Google Scholar
17. Enig, M.G., L.A. Pallansch, J. Sampugna and M. Keeney, —Ibid. 60:1788 (1983).
    CAS Google Scholar
18. Slover, H.T., R.H. Thompson, Jr., C.S. Davis and G.V. Merola, —Ibid. 62:775 (1985).
    Article CAS Google Scholar
19. Sebedio, J.-L., A. Grandgirard, C. Septier and J. Prevost,Rev. Fr. Corps Gras 34:15 (1987).
    CAS Google Scholar

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Authors and Affiliations

1. Institut des Sciences et Techniques des Aliments de Bordeaux, Laboratoire de Lipochimie Alimentaire, Universite de Bordeaux I, Allee des Facultes, 33405, Talence Cedex, France
   Robert L. Wolff

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Wolff, R.L. _trans_-Polyunsaturated fatty acids in French edible rapeseed and soybean oils.J Am Oil Chem Soc 69, 106–110 (1992). https://doi.org/10.1007/BF02540558

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• Received: 18 June 1991
• Accepted: 23 October 1991
• Issue date: February 1992
• DOI: https://doi.org/10.1007/BF02540558

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