Determination of Furan Fatty Acids in Extra Virgin Olive Oil

Abstract

The presence of 4 different furan fatty acids (F-acids) was detected in 18 samples of transmethylated monovarietal extra virgin olive oil: methyl 10,13-epoxy-11,12-dimethyloctadeca-10,12-dienoate [diMeF(9,5)], methyl 12,15-epoxy-13,14-dimethyleicosa-12,14-dienoate [diMeF(11,5)] and both olefinic derivatives of diMeF(11,5) with one unsaturation on the side chains conjugated with the furan ring. Transmethylated oils were analyzed by normal phase high-performance liquid chromatography coupled on-line with capillary gas chromatography. After the gas chromatographic separation step, a more selective detection of F-acids was achieved by using a photoionization detector mounted in series with a flame ionization detector. The concentration of F-acids ranged between 50 ppb (detection limit of the method) and 2.1 ppm in the oil. The olefinic derivatives of diMeF(11,5) acids detected were not artifacts created during the sample preparation or during the chromatographic analysis.

Detailed Study of Furan Fatty Acids in Total Lipids and the Cholesteryl Ester Fraction of Fish Liver

“…The hydrogen atoms in β-and β′-position can be substituted with methyl groups or just by one methyl group in β-position, i.e., adjacent to the carboxyalkyl chain. Besides the saturated F-acids, homologues with double bonds in the carboxyalkyl chain and alkyl chain have also been described in food samples (Pacetti et al 2010;Ishii et al 1988a;Boselli et al 2000). F-acids are known to act as radical scavengers (Okada et al 1996;Wakimoto et al 2011;Okada et al 1990; Lemke et al 2014) and are thus considered as valuable, bioactive minor fatty acids in food (Spiteller 2005;Pacetti et al 2013b;Vetter and Wendlinger 2013).…”

“…F-acids are known to act as radical scavengers (Okada et al 1996;Wakimoto et al 2011;Okada et al 1990; Lemke et al 2014) and are thus considered as valuable, bioactive minor fatty acids in food (Spiteller 2005;Pacetti et al 2013b;Vetter and Wendlinger 2013). F-acids have frequently been reported in the lipids of fish (Glass et al 1974;Gunstone et al 1978;Wahl et al 1994;Pacetti et al 2010), plants (Hannemann et al 1989), in oils (Boselli et al 2000;Guth and Grosch 1991), and butter (Guth and Grosch 1992), with fish being the richest nutritional source (Wendlinger and Vetter 2014). Unlike the usually low contribution to food lipids, F-acids were reported to be major fatty acids in the cholesteryl ester fraction of fish liver (Glass et al 1974(Glass et al , 1977Hammann et al 2015).…”

Analysis of pesticide residues by on‐line reversed‐phase liquid chromatography–gas chromatography in the oil from olives grown in an experimental plot

“…The classes of compounds to be analysed are prefractionated by LC and then transferred on-line to the GC system for analysis. 9,10 LC-GC has been applied to the analysis of the composition of minor components 11,12 and contaminants 13 in edible oils. Automated coupled on-line LC-GC systems have numerous advantages, especially when a large number of samples are to be analysed.…”

Analysis of Intact Cholesteryl Esters of Furan Fatty Acids in Cod Liver

“…Since then, they have been repeatedly detected in lipids of other fish, plants and milk fat [2,[6][7][8][9][10]. However, fish remains the type of food with the highest amounts of F-acids per gram fat [4].…”

“…Gas chromatography was reported to offer better resolution, but due to the low volatility of intact CEs, high temperatures are necessary [13,14]. Analysis of F-acids (usually as methyl esters), on the other hand, is exclusively performed by gas chromatography with flame ionization detection (GC/FID) or coupled to mass spectrometry (GC/MS) [2,[7][8][9][10]. Accordingly, data about the elution order and GC/MS spectra are available, which is not the case for HPLC.…”