Potential and Challenges of Applying Vibrational Spectroscopy to the Analysis of Trans Fats in Foods for Regulatory Compliance in theUSA

Abstract

Trans fatty acids are found in a variety of foods like dairy and meat products, but the major dietary sources are products that contain commercially hydrogenated fats. There has been a renewed need for accurate analytical methods for the quantification of total trans fat since declaration of the amount of trans fat present in food products and dietary supplements was made mandatory in many countries. Official capillary GC and IR methodologies are the two most common validated methods used to identify and quantify trans fatty acids for regulatory compliance. The present chapter provides a comprehensive discussion of the IR techniques, including the latest attenuated total reflection (ATR) Fourier transform (FT) IR methodology called the negative second derivative ATR/FT‐IR method, which has been validated in an international collaborative study. This chapter points to potential sources of interferences in the FTIR determination that may lead to inaccurate results, particularly at low trans levels. The presence of high levels of saturated fats may lead to interferences in the FTIR spectra observed for trans triacylglycerols (TAG). TAGs require no derivatization, but have to be melted prior to IR measurement. While GC is currently the method of choice, ATR/FT‐IR spectroscopy is a viable, rapid alternative, and complementary method to GC for a more rapid determination of total trans fats for food‐labeling purposes.