Abstract:A review taking into account the literature reports covering 20 years of fatty acid analysis by capillary electrophoresis is presented. This paper describes the evolution of fatty acid analysis using different CE modes such as capillary zone electrophoresis, non-aqueous capillary electrophoresis, micellar electrokinetic capillary chromatography and microemulsion electrokinetic chromatography employing different detection systems, such as ultraviolet-visible, capacitively coupled contactless conductivity, laser-induced fluorescence and mass spectrometry. In summary, the present review signals that CE seems to be an interesting analytical separation technique that is very useful for screening analysis or quantification of the usual fatty acids present in different matrices, offering short analysis times and a simple sample preparation step as inherent advantages in comparison with the classical methodology, making it a separation technique that is very attractive for quality control in industry and government agencies.

The main advantage to the proposed method is the possibility to observe the individual amount of the free fatty acids, which would be useful for researchers interested in studying the effect of the free fatty acids profile on oxidative process in food.

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There are few studies about different types of chocolate and their chemical characterization by Fourier transform (FT)-Raman spectroscopy and capillary zone electrophoresis (CZE). The aim of this study was to evaluate the lipid profile of different types of Brazilian chocolate through characterization by FT-Raman spectroscopy and identification and quantification of major fatty acids (FAs) by CZE to confirm FT-Raman spectrometry results. It was found that the main spectroscopic profile difference of the chocolate samples analyzed was related to the presence of saturated or unsaturated FAs. Well defined bands at approximately 1660, 1267, and 1274 cm(-1) corresponding to vibrational modes of unsaturated FAs (UnFAs) were found only in the spectra of samples with cocoa butter in their composition according to label specifications, mainly in dark chocolate samples. The FA identification and quantification by CZE found the presence of stearic (18:0) and palmitic (16:0) acids as the major saturated FAs in all chocolate samples. Dark chocolate samples showed the highest levels of oleic (cis-9 18:1) and linoleic (cis, cis -9,12 18:2) UnFAs monitored and the lowest levels of 14:0 in their chemical composition. Samples coded as 02 (with not only cocoa butter in their composition according to label) had the highest levels of 14:0 (FA not present in cocoa butter composition) corresponding to label information and inferring the presence of other fat sources, called cocoa butter substitutes, mainly for milk and white chocolate samples. This study suggests FT-Raman spectroscopy is a powerful technique that can be used to chemically characterize the chocolate lipid fraction, and CZE is a tool able to confirm Raman spectroscopy results and identify and quantify the major FAs in chocolate samples.

An alternative method for extraction optimization of C18:2 n-6 and C18:3 n-3, the main precursors for the synthesis of conjugated linoleic acid (CLA), in Brachiaria ruzizienses forages was proposed. Three methods of lipid extraction were tested: 1. Hara & Radin, 2. Micro Folch and 3. Bligh & Dyer. The preliminary test showed the Hara & Radin method as the most promising procedure. Then, a 33 Box Behnken design with triplicate in the central point was applied in Hara & Radin method in order to optimize the extraction procedure. The optimization extraction was monitored by quantification of C18:2 n-6 and C18:3 n-3 through capillary zone electrophoresis (CZE). The results obtained by CZE were compared to gas chromatography (AOCS official method) in real samples using the paired t-test. No significant difference between methods was found within a 95% confidence interval (p-value= 0.937). The alternative CZE method for Brachiaria ruzizienses forages analysis has some advantages in comparison with official GC method such as, short analysis time (10 min), no derivatization step for sample preparation, absence of specific separation columns, lower analytical cost and high throughput.