CONJUGATED LINOLEIC ACID AND FATTY ACID ISOMERS IN SELECTED COLD PRESSED OILS: ANALYSIS BY GC/FID TECHNIQUE

Abstract

The conjugated linoleic acid (CLA) isomers in cold pressed oils [pomegranate seed oil (PGSO), linseed oil (LSO), black cumin seed oil (BCSO), nettle seed oil (NSO),grape seed oil (GSO), sesame seed oil (SSO),safflower oil (SFO), pumpkin seed oil (PSO), wheat germ oil (WGO), fig seed oil (FSO), coriander oil (CO), walnut oil (WO) and coconut oil (CNO)] extracted with lab–scale screw press machine were further subjected to gas chromatography/flame ionization detection (GC/FID) analysis. The composition of polyunsaturated fatty acids (PUFAs), monounsaturated fatty acids (MUFA) and saturated fatty acids (SFAs) of the samples was also determined. The five different positional and geometric isomers of CLA [cis–9, cis–11 CLA, cis–9, trans–11 CLA, trans–9, cis–11 CLA, trans–9, trans–11 CLA and trans–10, cis–12 CLA] were also well separated by a highly polar column (100m×0.2μm×0.25mm i.d; HP–88 cyanopropyl) and an applied GC temperature program. It was concluded that the samples were all rich in total CLA (∑CLA) and they were found between 0.14% for PSO and 2.11% for SSO. The most abundant CLA isomer was in general to be cis–9, trans–11 CLA form, which represented the content of isomer between 3.15% and 72.08% of ∑CLA. Besides, the ∑SFA values were detected between 2.43% and 93.14%, ∑MUFA values were between 4.60% and 71.11% and ∑PUFA values were between 1.79% and 87.59%. Therefore, this study might offer valuable information for the introduction of new food sources, as well as incorporation into medicinal purposes and food formulations which have the potential to be commercially valuable.