Although it is known that most of the fatty acids found in nature are in cis form, trans fatty acids, which is a popular topic in nutritional physiology, are not naturally found in fats and they are mostly technological (partial hydrogenation, refining and partially frying). applications. With the development of capillary column gas chromatography method, trans isomers of fatty acids in various vegetable and animal oils have been easily identified. During the formation of milk in the rumen of cows, sheep, goats and other ruminants, Trans faty acid also occurs as a result of biological hydrogenation. Trans fatty acid is a form of geometric isomer seen in unsaturated fatty acids containing at least one double bond. Unsaturated fatty acids include two different isomeric structures, geometric and position isomers. This isomerism, depending on the configuration of the structure of hydrogen atoms in the form of cis and trans are available in two forms (Gunstone, 1986; Kayahan, 2002; Kiralan et al. 2006). Cis isomers are formed if the hydrogen atoms are on the same side of the carbon chain and trans isomers are formed.
The double bond angle in the trans form is smaller than the cis form and the acyl chain is more linear. Because of this feature, the trans form, which has a more stable (higher melting point and thermo-dynamic stability) molecular structure than the cis form, melts at higher temperatures. For example, the cis form of oleic acid melts at 13.4 ºC and its trans form elaidic acid (C18: 1 t) melts at 43.5-45.5 ºC. This makes trans isomers attractive for the production of semi-solid oils and margarine / shortsening (Kayahan 2002; Kıralan 2006).
Nowadays, refined vegetable oils and pomace oil are used for adulteration in olive oil which is in the foreground as an important fat source of healthy nutrition. Various methods are used in the determination of these. Chromatographic methods are at the forefront of these methods. Analyzes are made on different criteria in determining the adulteration of different oils in olive oil. As a result, for the determination of adulteration in olive oil, adulteration control is performed by applying different criteria analyzes for refined vegetable oils and pomace oil.
The content of trans fatty acids of olive oil: Fatty acids normally in the form of -cis can be converted into raftrans form by refining process. If refined vegetable oil is added to olive oil which is not refined, the trans oil content and adulteration can be detected. Gas chromotography is used for the detection of trans fatty acids.
RESOURCES: Kayahan, M., 2002. Modifiye Yağlar ve Üretim Teknolojileri. METU Press. Ankara. Kıralan, M., Yorulmaz, A., Erçoşkun,M.,2006. Trans yağ asitleri kaynakları, ve insan sağlığı üzerine etkileri. Gıda ve Yem Bilimi – Teknolojisi. 7 : 62 – 64. YORULMAZ, A. (2009). TÜRK ZEYTİNYAĞLARININ FENOLİK, STEROL VE TRİGLİSERİT YAPILARININ BELİRLENMESİ. s. 14-25.