MONOCYCLIC SATURATED FATTY-ACIDS FORMED FROM OLEIC-ACID IN HEATED SUNFLOWER OILS

Fractions of saturated cyclic fatty acids, formed from oleic acid in n ormal and high-oleate sunflower oils during small-scale frying operati ons, were isolated by silver ion high-performance liquid chromatograph y. By means of gas chromatography of the methyl esters and gas chromat ography/mass spectrometry of the dimethyloxazoline derivatives, eight monocyclic saturated fatty acids, comprising four basic structures, we re identified: cyclopentyl fatty acids with rings from C-5 to C-9 and C-10 to C-14, and cyclohexyl fatty acids with rings from C-4 to C-9 an d C-10 to C-15 of the original fatty acid chain. Each structure was re presented by two components corresponding to cis and trans ring isomer s. The cyclopentyl fatty acids were twice as abundant as those with a cyclohexane ring. Possible mechanisms for formation of the cyclic fatt y acids via radical intermediates are discussed.