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Determination of the fatty acids composition in selected shortenings
RAZIMOVÁ, Jana
The objective of this work is to get acquainted with methods for determination of fatty acids profile, especially with gas chromatography using the flame ionization detector and the mass spectrometer. The first part of the work deals with lipids classification, summary of fatty acids and their properties. It contains also a draft of edible fats division and their production. Other section deals with ways of determination of fatty acids in fats and puts the main emphasis on gas chromatography. The second part deals with the determination of fatty acids in selected shortening fats (Hera, Stela, Zlatá Haná, Sluna, Perla máslová, Flora, Rama máslová, Alfa máslová) in practice. Three measurements were taken at three months intervals. There were taken three samples from each fat during each sampling, it means 72 samples were taken in total. Samples had to be adjusted to increase their volatility. In this case specifically the esterification was made where fatty acids were transformed into fatty acids methyl esters. The measurement was made by the flame chromatograph using the flame ionization detector and the mass spectometer. For final samples evaluation softwares MS Worsktations 6.9, Microsoft Excel ? Statistical programs and software Statistica by Stat Soft ČR, s.r.o. were used. The prevailing fatty acid in all fats is oleic acid. Another acid widely presented in all fats is palmitoleic acid. The only exception is fat Flora where linoleic acid has the biggest percentage. Fatty acids typical for milk fat (butyric and caproic acids, TFA and acids with odd number of carbon atoms (C15 a C17)) are chiefly presented in fat Zlatá Haná. In other fats these fatty acids are found just in small quantities. By comparing single samplings it becomes clear that they are more or less different. The reason of these differences lies probably in fats mixing. That is why during production some small differences in their composition may occur. The principal komponent analysis shows that Zlatá Haná is the most different fat. The reason is that this fat contains the most fatty acids typical for milk fat. Another separate group is represented by fat Flora where the biggest quantity of polyunsaturated fatty acids (linoleic acid) can be found. Fats Stela and Sluna have very similar fatty acids compositions, the prevailing fatty acids are oleic acid and palmitoleic acid. That is also the case of Perla máslová and Rama máslová where even linoleic acid was found in quite a big quantity.
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Determination of the fatty acids composition in selected hardened fats
JANEŠÍKOVÁ, Kristina
The aim of this work is to get oneself acquainted with the method of spectrum evaluation of fatty acids in hardened fats by means of gas chromatography and mass spectrometry. The theoretical part deals with information concerning the types of lipids, their compositions, properties of fatty acids especially in oils and hardened cooking fats and with basic information regarding the methods of oil hardening. This part is concentrated on the evaluation method of fatty acids by means of gas chromatography with the use of gualitative using the mass spectrometry. The fatty acids were evaluated in some commercially available fats (Albert, Ceres Soft, Iva, Lando, Lira, Omega, Varoma). Palmitic acid (hexadecane acid) was represented in the highest proportion in all fats, it was 36-45.5%, frequently represented was also oleic acid (cis-octadec-9-ane) with its 32.2-39%. The last of the more frequently represented acids is the linoleic acid (cis, cis-octadeca-9.12-diene) with its 7.7% to 10.5%. A lower amount of the linoleic acid is contained in the Albert fat, where it is represented with 4.5% only. Interesting is the content of acids being typical for milk fat of ruminants, it includes the caprylic acid (octane), capric acid (decane) and lauric acid (dodecane) and the content of trans-acids. The hardened Albert fat has the highest content of trans-acids, they occupy 23.4% of the product. On the base of this result it can be deducted that this product has probably a lower quality than other ones. In comparison with other fats, the content of acid typical for milk fakt is higher in the Lando and Iva fats. This results indicate the milk fat was probably added in these products during the production. In the time period of one year no considerable changes in the composition of selected hardened fats were registered, however, from the long termed point-of-view, there is an evident marked alternation in the composition of the Ceres Soft and Omega hardened fats being accompanied with a basic decrease of trans-acids.
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