High field¹³C nuclear magnetic resonance spectrum of the olefinic carbons of the triglycerides of palm oil

Abstract

In the triglycerides of palm oil (or any vegetable oil or fat), an unsaturated fatty acid (oleic or linoleic) attached to the 2‐glycerol carbon can be distinguished from one attached to the 1‐ or 3‐glycerol carbon by high (or medium) field13C nuclear magnetic resonance (NMR) analysis of the olefinic carbons. The chemical shift difference of the olefinic carbons in the fatty acid chain is characteristic of the chain's glycerol position and can therefore be used to identify the glycerol position of an unsaturated fatty acid in the triglyceride.

High‐resolution nuclear magnetic resonance spectroscopy —Applications to fatty acids and triacylglycerols

“…The report indicated that, except for the lack of differentiation of the saturated fatty acids, the 13 C NMR technique provided the same information as the tedious enzymatic hydrolysis cum fatty acid analysis (88). The chemical shift difference of the olefinic carbon atoms in the fatty acid chain of triacylglycerols in palm oil was found to be characteristic of the chain's glycerol position and can therefore be used to identify the glycerol position of an unsaturated fatty acid in the triacylglycerol molecule (89).…”

High field ¹³C NMR spectroscopic analysis of the triacylglycerols of <i>Adenopus Breviflorus</i> seeds oil

“…A high (or medium) field 13 C NMR spectrum can distinguish the olefinic carbons of the β-chain from those of the -chain [3]. The assignment of the signals to the olefinic carbons of the fatty acid chain attached to the α or β glyceridic positions presented in Figure 1 were done as described by Ng [3].…”

“…The assignment of the signals to the olefinic carbons of the fatty acid chain attached to the α or β glyceridic positions presented in Figure 1 were done as described by Ng [3]. Integration of the pair of peaks for C-9 of the oleic chain and of the pair of peaks for C-10 of the linoleic chain in a spectrum obtained under suitable condition of gated decoupling, permits quantitative analysis of the unsaturated chain attached to the and β positions Tulloch [18].…”

“…Carbon-13 NMR has been shown to be an adequate method for defining both the acyl distribution and positional placement on the glycerol backbone in triacylglycerols [1][2][3]. The advantages of NMR technique in achieving these goals over other techniques like highperformance liquid chromatography [4][5], supercritical fluid chromatography [6] and gas chromatography [7,8] derive from the following facts.…”

“…There are ten signals in this region. Ng [3] observed that the chemical shift between a pair of peaks becomes smaller for the olefinic carbon nearer to the methyl end of the fatty acid chain, i.e. in the oleic chain, magnitude of peak separation is in the order C-9 > C-10 and in the linoleic chain the order is C-9 > C-10 > C12 > C-13.…”