Rapid determination of cis and trans content, iodine value, and saponification number of edible oils by Fourier transform near-infrared spectroscopy

Fourier transform near-infrared (FT-NIR) spectroscopy was evaluated as a me ans of simultaneously determining the cis and trans content, iodine value ( IV), and saponification number of neat fats and oils. Reference values for these parameters were obtained from oils using a previously developed mid-F TIR Edible Oil Analysis Package. Two partial least squares calibrations wer e developed for a 5-mm heated flow cell, the first a process calibration ba sed on hydrogenated soybean samples and the second a more generalized calib ration based on an oil sample matrix containing many oil types and designed to remove any correlations among the parameters measured. Each calibration performed well with its own validation samples; however, only the noncorre lated calibration was able to analyze oil samples accurately from a variety of sources. It was found that NIR analysis maintained the internal consist ency between cis/trans and IV, and the accuracy and reproducibility of the predictions were on the order of +/-1.5 and +/-1.0 units, respectively, for all parameters evaluated. FT-NIR is shown to be a very workable means of d etermining cis/trans/IV values and saponification number for edible fats an d oils, and it provides a rapid alternative to the commonly used chemical a nd physical methods presently employed in the industry.