Trans-fat Analysis for Nutrition Facts
Unfortunately, the nutritional databases and/or software packages that so many companies use to prepare their Nutrition Facts statements are not set up to calculate levels of trans fatty acids. Both the USDA and FDA have developed some data, but these data are not extensive. Databases that include trans fats need to be fully developed. In the interim, the industry must turn to chemistry to determine levels of trans fatty acids in foods.
Covance Laboratories (Madison, Wis.) can provide these services to the food industry. The chemistry staff at Covance evaluates and makes any necessary modifications to the different methods for determining trans fats in foods. Existing methods include those found in the Official Methods of the AOAC (Association of Official Analytical Chemists) and those published by the AOCS (American Oil Chemists Society).
Both the AOAC and AOCS procedures include protocols that use infrared spectrophotometry (IR), gas chromatography (GC) and a combination of the two methods (GC-IR). Currently, Covance scientists are working to optimize the procedures using GC.
Barb Mitchell, senior chemist at Covance, and others believe that the GC methods are the most versatile and offer the best specificity. In fact, the consensus is that AOAC method 996.06, which uses a GC, may be the best of the methods. The GC protocols are the most sensitive when working with products with low concentrations of trans acids. Furthermore, they are less likely to overestimate trans levels, as IR procedures sometimes do.
This does not imply that the GC methods are perfect, though. In many cases, the extraction procedures described in the official methods are not well-defined. Longer columns are needed to properly separate and quantify the different trans acids. Covance's research is geared to optimize these methods so that clients receive accurate and repeatable results.
For more information:Covance Laboratories, Wayne Ellefson