Heat treatment of vegetable oils III. GC‐MS characterization of cyclic fatty acid monomers in heated sunflower and linseed oils after total hydrogenation

Abstract

AbstractFractions of cyclic fatty acid monomers (CFAM) were isolated from linseed oil heated at 275°C for 12 hr under nitrogen, at 240°C for 10 hr under nitrogen and at 240°C for 10 hr under air. Cyclic fatty acid monomers fractions were also isolated from a sunflower oil heated at 275°C for 12 hr under nitrogen and at 200°C for 48 hr in a commercial fryer. The CFAM fractions were hydrogenated and their composition studied by gas liquid chromatography coupled with mass spectrometry (GC‐MS). The CFAM in the fraction isolated from heated linseed oil samples were a mixture (1:1) ofcis andtrans cyclopentyl and cyclohexyl isomers, while the CFAM in the fractions isolated from heated sunflower oils were mostly cyclopentyl isomers. The major cyclopentyl isomers weretrans andcis methyl 7‐(2′‐hexylcyclopentyl) ‐heptanoate, methyl 9‐(2′‐butyl‐cyclopentyl)‐nonanoate and methyl 10‐(2′‐propylcyclo‐pentyl)‐decanoate. The major cyclohexyl isomers were thetrans andcis methyl 9‐(2′‐propylcyclohexyl)‐nonanoate which represented about 50% of the CFAM isomers isolated from heated linseed oil samples.