Abstract
A Fourier transform infrared (FTIR) edible oil analysis package designed to simultaneously analyze for trans content, cis content, iodine value (IV), and saponification number (SN) of neat fats and oils by using calibrations based on pure triglycerides and derived by application of partial-least-squares (PLS) regression was assessed and validated. More than 100 hydrogenated rapeseed and soybean samples were analyzed by using the edible oil analysis package as well as the newly proposed modification of the AOCS IR trans method with trielaidin in a trans-free oil as a basis for calibration. In addition, ∼1/3 of the samples were subsequently reanalyzed by gas chromatography (GC) for IV and trans content. The PLS approach predicted somewhat higher trans values than the modified AOCS IR method, which was traced to a combination of the inclusion of trilinolelaidin in the calibration set and the effects of baseline fluctuations. Eliminating trilinolelaidin from the triglyceride standards and the use of second-derivative spectra to remove baseline fluctuations produced excellent concurrence between the PLS and modified AOCS IR methods (mean difference of 0.61% trans). Excellent internal consistency was obtained between the IV and cis and trans data provided by the edible oil analysis package, and the relationship was close to that theoretically expected [IV=0.86 (cis + trans)]. The IV data calculated for the GC-analyzed samples matched the PLS IV predictions within 1 IV unit. The trans results obtained by both IR methods were linearly related to the GC data; however, as is commonly observed, the GC values were significantly lower than the IR values, the GC and IR data being related by a slope factor of ∼0.88, with an SD of ∼0.80. The concurrence between the trans data obtained by the two FTIR methods, and between the FTIR and GC-IV data, as well as the internal consistency of the IV, cis and trans FTIR predictions, provides strong experimental evidence that the edible oil analytical package measures all three variables accurately.
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References
Gurr, M., A Fresh Look at Dietary Recommendations, INFORM 7:432–435 (1996).
Anon., Controversy: Three Nations Wrestle with Trans Issue, Ibid. 6:1148–1149 (1995).
van de Voort, F.R., J. Sedman, G. Emo, and A.A. Ismail, Rapid and Direct Iodine Value and Saponification Number Determination of Fats and Oils by Attenuated Total Reflectance/Fourier Transform Infrared Spectroscopy. J. Am. Oil Chem. Soc. 69:1118–1123 (1992).
Ismail, A.A., F.R. van de Voort, G. Emo, and J. Sedman, Rapid Quantitative Determination of Free Fatty Acids in Fats and Oils by FTIR Spectroscopy, Ibid.:335–341 (1993).
van de Voort, F.R., A.A. Ismail, J. Sedman, J. Dubois, and T. Nicodemo, The Determination of Peroxide Value by Fourier Transform Infrared Spectroscopy, Ibid.:921–926 (1994).
van de Voort, F.R., FTIR Spectroscopy in Edible Oil Analysis, INFORM 5:1038–1042 (1994).
van de Voort, F.R., A.A. Ismail, J. Sedman, and G. Emo, Monitoring the Oxidation of Edible Oils by FTIR Spectroscopy, J. Am. Oil Chem. Soc. 71:243–253 (1994).
van de Voort, F.R., A.A. Ismail, and J. Sedman, A Rapid Determination of Cis and Trans Content of Fats and Oils by FTIR Spectroscopy, Ibid.:873–880 (1995).
van de Voort, F.R., P. Memon, J. Sedman, and A.A. Ismail, Determination of Solid Fat Index by FTIR Spectroscopy, Ibid.:411–416 (1996).
Dubois, J., F.R. van de Voort, J. Sedman, A.A. Ismail, and H. Ramaswamy, Quantitative FTIR Analysis of Anisidine Value and Aldehydes in Thermally Stressed Oils, Ibid.:787–794 (1996).
Mossoba, M., M.P. Yurawecz, and R.E. McDonald, Rapid Determination of the Total Trans Content of Neat Hydrogenated Oils by Attenuated Total Reflection Spectroscopy, Ibid.:1003–1009 (1996).
Official Methods and Recommended Practices of the American Oil Chemists’ Society, 4th edn., American Oil Chemists’ Society, Champaign, 1989.
Youden, W.J., and E.H. Steiner, Statistical Manual of the AOAC, Association of Official Analytical Chemists, Arlington, 1975.
Sleeter, R.T., and M.G. Matlock, Automated Quantitative Analysis of Isolated (Non-conjugated) Trans Isomers Using Fourier Transform Infrared Spectroscopy Incorporating Improvements in the Procedure. J. Am. Oil Chem. Soc. 66:121–127 (1989).
Ulberth, F., and H.J. Haider, Determination of Low Level Trans Unsaturation in Fats by Fourier Transform Infrared Spectroscopy, J. Food Sci. 57:1443–1447 (1992).
Firestone, D., General Referee Reports; Fats and Oils, J. Assoc. Off. Anal. Chem. Int. 79:216–220 (1996).
Mossoba, M.M, and D. Firestone, New Methods for Fat Analysis in Foods, Food Testing and Analysis 2:24–32 (1996).
Haaland, D.M., and E.V. Thomas, Partial-least-squares Methods for Spectral Analyses. I. Relation to Other Quantitative Calibration Methods and the Extraction of Qualitative Information, Anal. Chem. 60:1193–1202 (1988).
Ratnayake, W.M.N., Determination of Trans Unsaturation by Infrared Spectrophotometry and Determination of Fatty Acid Composition of Partially Hydrogenated Vegetable Oils by Gas Chromatography/Infrared Spectrophotometry: Collaborative Study, J. Assoc. Off. Anal. Chem. Int. 78:783–802 (1995).
Sedman, J., F.R. van de Voort, and A.A. Ismail, Upgrading the AOCS Infrared trans, Method for Analysis of Neat Fats and Oils by Fourier Transform Infrared Spectroscopy, J. Am. Oil. Chem. Soc. 74:907–913 (1997).
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Co-Director, McGill IR Group.
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Sedman, J., van de Voort, F.R., Ismail, A.A. et al. Industrial validation of fourier transform infrared trans and lodine value analyses of fats and oils. J Amer Oil Chem Soc 75, 33–39 (1998). https://doi.org/10.1007/s11746-998-0006-y
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DOI: https://doi.org/10.1007/s11746-998-0006-y