A simple methodology for the determination of fatty acid composition in edible oils through ¹H NMR spectroscopy

Abstract

A simple methodology for the determination of the fatty acid composition of edible oils through (1)H NMR is proposed. The method is based on the fact that all fatty acid chains are esterified to a common moiety, glycerol, and the quantification is done directly in the (1)H NMR spectra through the relationship between the areas of a characteristic signal of each fatty acid and a signal of the glycerol moiety, without the use of mathematical equations. The methodology was successfully applied to determine the fatty acid composition of several edible oils, with equivalent results to those given by the AOAC Official method by gas chromatography. Its main advantages are simplicity and the lack of need for sample pre-treatment such as derivatization or extraction.

Physicochemical Properties and Structural Characterisation of Fatty Acids Derived from Jatropha curcas Oil Using Microwave Assisted Alkaline Hydrolysis

“…Figure 3 shows the characteristic signals at 0.8-0.9 ppm for methyl (-CH 3 ) group proton, 1.0 to 1.8 ppm signal for methylene (-CH 2 ) proton, 2.0 to 2.1 ppm signal for proton attached to allylic carbons corresponding to the Salimon et al 8 The allylic carbon arose from carbon attached to carbon double bonds (-H-C-C=CH) whereas the peak at 5.8 ppm arose from proton attached to carbon double bonds (HC=CH). Broad peak at 10 to 12.1 ppm corresponds to carboxyl groups as reported by Barison et al 17 Figure 3: Comparison of proton spectra of fatty acids between (a) synthesised and (b) standard oleic acids.…”

Tunisian Extra Virgin Olive Oil Traceability in the EEC Market: Tunisian/Italian (Coratina) EVOOs Blend as a Case Study

“…The relaxation delay (RD) and acquisition time (AQ) were set to 4 s and~3.98 s, respectively, resulting in a total recycle time of~7.98 s. Free Induction Decays (FIDs) were collected into time domain (TD) = 65,536 (64 k) complex data points by setting: spectral width (SW) = 20.5524 ppm (8223.685 Hz), receiver gain (RG) = 4, number of scans (NS) = 16. An accumulation of 16 scans (or even fewer) are usually used for samples where metabolites are present in high concentrations, as in the case of olive oil [19,28].…”

Characterization of Leucaena (<em>Leucaena leucephala</em>) oil by direct analysis in real time (DART) ion source and gas chromatography

“…On the other hand, fatty acid composition not only depends on species but on region, climate, degree of ripeness, harvesting and processing conditions. LUCO is rich in Linoleic acid (52.08%); the fraction analyzed contains palmitic, stearic, oleic, linolenic, arachidic, gadoleic, and behenic acid (Nehdi et al, 2013(Nehdi et al, , 2014 (Figure 2) (Barison et al, 2010). (Figure 4) (Alam et al, 2014).…”