Validation and application of a chromatographic method for evaluation of commercial vegetable oils possibly adulterated

Abstract

A method of separation, identification and quantification of fatty acid methyl esters (FAMEs) was developed by gas chromatography with flame ionization detector (GC-FID) using a basic transesterification. In this sense, there were analyzed FAMEs in commercial samples of vegetable oils from soybean and olive oil. The referred method was linear (r>0.99), accurate and precise for palmitic (C16:0), linoleic (C18:2), oleic (C18:2), linolenic (C18:3) and stearic (C18:0) acids. The limits of detection (LOD) and quantification (LOQ) were from 0.03 to 0.31 and 0.08 to 0.94 mg.mL-1 for the five fatty acids, respectively. The results demonstrated that the unsaturated fatty acids were the most abundant for the two samples, being the oleic acid (C18:1) the major in three brands of olive oil (D, E and F), and the linoleic acid (C18:2) the most abundant in soybean oil and the other brands of olive oil (G, H and I), suggesting a possible adulteration in these brands. The proposed method could be considered a tool for the investigation of adulteration in commercial vegetable oils for guaranteed reliability in the results to be comparable with correlated legislations.

A preliminary study of the physico-chemical properties and fatty acid profile of five palm oil genotypes cultivated in Northeast of Brazil

“…The oil (25 mg) of each sample, in triplicate, were transesterified by the addition of 0.5 mL of KOH in methanol (0.5 mol.L -1 ), subsequently vortexed (2 min) and added 2 mL of n-hexane. Samples were shaken again (2 min), centrifuged (4500 rpm, 6 min, 25°C) and filtered supernatant (0.44 μm) and packed in vials for further analysis (Araújo et al, 2018).…”