Evaluation of the Performance of a Portable Mid-Infrared Analyzer for the Rapid Determination of Total Trans Fat in Fast Food

The performance of a novel, transmission-mode, portable, Fourier transform infrared (FTIR) analyzer was evaluated and compared to that of a benchtop attenuated total reflection (ATR)-FTIR spectrometer. The total concentration of trans fatty acids in the fat extracted from 19 representative fast foods was rapidly (< 5 min) quantified in a single measurement after conversion to fatty acid methyl esters (FAME). While the FTIR determination is rapid, the time required for extraction and derivatization is not. For all extracts, the total trans FAME concentration varied from approximately 0.5 to 11 % (of total FAME) as determined using the portable FTIR analyzer. The trans fat contents (mean +/- A SD), expressed in grams per serving and calculated on the basis of total fat content and FTIR determination of trans fat content, were found to be 1.00 +/- A 0.42 for hamburgers, 0.67 +/- A 0.78 for chicken tenders, 1.00 +/- A 1.24 for French fries, and 0.27 +/- A 0.23 for apple pies. Determinations of total trans-unsaturated FAME were consistent with those obtained by use of ATR-FTIR and GC official methods (AOCS Cd 14e-09 and AOCS Ce 1j-07, respectively). These results indicate that the portable FTIR analyzer is suitable for the rapid and routine quantification of total trans fat measured as FAME prepared from fats extracted from fast foods.