Regulatory Infrared Spectroscopic Method for the Rapid Determination of Total Isolated Trans Fat: A Collaborative Study

• Published in: Journal of the American Oil Chemists' Society 2011-01, Vol.88 (1), p.39-46
• Main Authors: Mossoba, M. M., Seiler, A., Steinhart, H., Kramer, J. K. G., Rodrigues-Saona, L., Griffith, A. P., Pierceall, R., van de Voort, F. R., Sedman, J., Ismail, A. A., Barr, D., Da Costa Filho, P. A., Li, H., Zhang, Y., Liu, X., Bradley, M.
• Format: Article
• Language: English
• Subjects: Absorption; Agriculture; Biological and medical sciences; Biomaterials; Biotechnology; Chemistry; Chemistry and Materials Science; Fat industries; Fats and oils; Food industries; Food Science; Fourier transforms; Fundamental and applied biological sciences. Psychology; Industrial Chemistry/Chemical Engineering; Infrared; Lipid analysis; Lipid chemistry; Nutrition; Oils & fats; Organic solvents; Original Paper; Solvents; Spectroscopy; Spectrum analysis; Trans fats
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1007/s11746-010-1648-0

Using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, collaborating scientists in ten different laboratories measured (in duplicate) the total trans fat content of ten fat or oil test samples, two of which were blind duplicates. The procedure used entailed measuring the height of the negative second derivative of the IR absorption band at 966 cm −1 . This absorption is attributed to the C–H deformation vibration that is characteristic of isolated (non-conjugated) double bonds with the trans configuration. The precision of ATR-FTIR results in this international collaborative study was satisfactory and led to the approval of this validated procedure as official method AOCS Cd 14e-09 in late 2009. This official method is also suitable for analysis of total isolated trans fat and oil products containing, or supplemented with, trans conjugated linoleic acid (CLA) isomers. Although this method does not require derivatization of the oil or fat test materials, as required for GC, fats and oils in foods must be extracted with organic solvents before analysis. This method is also rapid (5 min) and does not require any weighing or quantitative dilution of unknown neat fat or oil test samples in any solvent. The AOCS Cd 14e-09 method is suitable for determination of test samples with zero trans fat, which is defined according to the US labeling regulations as 0.5 g trans fat per serving or 1.8% trans fat, as a percentage of total fat.