Interference of Saturated Fats in the Determination of Low Levels of trans Fats (below 0.5%) by Infrared Spectroscopy

• Published in: Journal of the American Oil Chemists' Society 2007-04, Vol.84 (4), p.339-342
• Main Authors: Mossoba, M. M, Kramer, J. K. G, Milosevic, V, Milosevic, M, Azizian, H
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; chemical analysis; Coconut oil; Fat industries; Fatty acids; food chemistry; Food industries; Fundamental and applied biological sciences. Psychology; Infrared spectroscopy; Nutrition; Oils & fats; saturated fatty acids; Trans fats; Vegetable oils
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1007/s11746-007-1038-4

The mandate to label food products with the content of total trans fatty acids has led to an increase in demand for sensitive and accurate methodologies for the rapid quantitation of trans fats. Unfortunately, the latest official infrared (IR) spectroscopic method lacks the required sensitivity. A more sensitive IR procedure that requires the measurement of the height of the second derivative (2D) of the trans absorption band at 966 cm-¹ was recently proposed; however, a reported inconsistency at low trans levels between GC (0% of total fat) and IR (1.2% of total fat) results for a fully hydrogenated vegetable oil could not be reconciled, and triggered further investigations. For the first time, we recognize and report the presence of weak interference bands (962-956 cm-¹) attributed to saturated fats in the IR spectra of trans fats; these interference bands have an adverse impact on the sensitivity and accuracy of the IR determination at low trans levels (