| Abstract |
Since the discovery of the hydrogenation process, saturated fatty acids hold the first place of consumers eating habits. After years of research, it has been shown that saturated fats are responsible for various diseases and in 2015, the Food and Drug Administration (FDA) required its full removal from all processed foods. The aim of this study, is the development of a method for the qualitative and quantitative determination of levels of trans-fatty acids in margarine samples, butters and oils which are sold in the Greek market.
To achieve this, a gas chromatography-mass spectrometry (GC-MS) technique and an attenuated total reflectance with a Fourier transform infrared spectroscopy technique (FTIR-ATR) was applied and their results were compared. Furthermore, these results were compared with similar studies in Greece, Europe and even on a worldwide level. Trans Fatty Acids (TFAs) are geometric isomers of monounsaturated and polyunsaturated fatty acids. Those which are detected and studied in the present work are t-oleic acid (C18:1), t, t- Linoleic acid (C18:2), and t,t,t- a- Linolenic acid (C18:3). Thirty-two butter and margarine samples and seven oil samples were collected and their preparation was done according to the methylation process. None of the analyzed samples, with the exception of the extra virgin olive oil, was trans free. Most of the samples had a total concentration of TFA lower than i% w/w ( <1% w/w) except for two, which showed a total TFA concentration of i.23 and i.55% w/w. The t,t- Linoleic acid (C18:2 ) is the one which prevails in most samples as compared to the t-oleic acid (C18:1), with an average concentration of 0.28% w/w and 0.14% w/w, respectively, while the t, t, t- a- Linolenic acid's (C18:3) concentration appeared to be only 0.11% w/w. As observed, margarine samples contained an average of 0,56% w/w TFA (0.26 up to 1.55% w/w), animal origin butters 0.45% w/w (0.21 up to 0.74 % w/w) and mixtures 0.54% w/w (0.37 up to 0,85% w/w).
In order to compare and correlate the obtained results from the two aforementioned techniques we used, a peak at 966 cm-1 from the FTIR spectra was used and showed a correlation between both methods. Both techniques are necessary though in order to obtain more valid results. Comparing the results of this study with similar studies, it was observed that over the years the concentration of these formulations in TFA decreased significantly. A study conducted in 1994 by A. Kafatos and his team, showed that the concentration of t-C18:1 ranged from 5.40 to 9.54% and t- C18:2 from 0.40 to 3.65%. In this study, the corresponding values were 0.16% (0.02- 1.12%) and 0.26% (0.04- 0.79%) and in recent studies the TFA levels were found to be lower than 1% w/w.
In comparison to other European countries (Transfair study), but also globally, the content of different formulations in TFA is significantly reduced with the Mediterranean countries having the least daily consumption rates of TFA. This is probably due to the way of preparing the various formulations, as the Mediterranean diet is based on extra virgin olive oil, which is TFA free.
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Διερεύνηση της περιεκτικότητας σε trans-λιπαρά φυτικών και ζωικών λιπαρών της ελληνικής αγοράς με χρήση GC-MS και FT-IR
