Detection of lactobacillic acid in low erucic rapeseed oil--A note of caution when quantifying cyclic fatty acid monomers in vegetable oils.
The purpose of this work was to identify an unknown component which has been detected during the analysis of cyclic fatty acid monomers (CFAMs) in low erucic acid rapeseed oils (LEAR). A sample of crude LEAR was transformed into fatty acid methyl esters (FAMEs) and hydrogenated using PtO(2). The hydrogenated sample was fractionated by reversed-phase high-performance liquid chromatography (RP-HPLC) and the fraction containing the CFAMs transformed into picolinyl esters. Analysing these picolinyl derivatives by gas-liquid chromatography coupled to mass spectrometry (GC-MS) showed that the unknown product observed in LEAR is the 11,12-methylene-octadecanoic acid. This cyclic fatty acid was also found in crude LEAR and in the corresponding seeds but was not detected in crude soya and sunflower oils. As this acid is present in the same fraction as CFAMs, known to be formed during heat treatment, great care must therefore be taken for not including it when quantifying CFAMs. It is thus necessary to verify by mass spectrometry the structures of the CFAMs in the isolated cyclic fatty acid fraction prior to quantification.
Berdeaux
Olivier
O
Plate-forme lipides-arômes, Centre des Sciences du Goût et de l'Alimentation, UMR6265 CNRS, UMR1324 INRA, Université de Bourgogne, Agrosup Dijon, F-21000 Dijon, France. berdeaux@dijon.inra.fr
Gregoire
Stéphane
S
Fournier
Cindie
C
Christie
William W
WW
Lambelet
Pierre
P
Sébédio
Jean-Louis
JL
D005227:Fatty Acids / Q000032:analysis*; D005229:Fatty Acids, Monounsaturated; D008401:Gas Chromatography-Mass Spectrometry; D010938:Plant Oils / Q000737:chemistry*; D000074262:Rapeseed Oil
D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D010938:Plant Oils; D000074262:Rapeseed Oil; C028716:phytomonic acid