Rapid and direct quantitative analysis of positional fatty acids in triacylglycerols using ¹³C NMR

Abstract

There is increasing evidence that the positional fatty acid composition (FAC) of TAG is more important than total FAC with regard to nutrition values of edible oils and fats. A rapid and direct regiospecific analysis of positional fatty acids in TAG using 13C NMR was developed to overcome the tedious conventional methods which involve enzymatic hydrolysis, Grignard chemical degradation, and chromatography analysis. A set of NMR data acquisition parameters and processing methods had proven their excellent versatility and applicability on various types of oils and fats, with systematic error of 1.0 mol%. It was found that there are discrepancies between the regiospecific analysis results obtained by the current method and by conventional methods. Probable acyl migration occurring in the hydrolysis process in conventional methods is a noted problem. As the current 13C NMR method is a direct measurement and no hydrolysis of the sample is needed, acyl migration during the analysis is eliminated. As a result, the saturation level is always higher at sn‐1, 3 positions and lower at sn‐2 position in TAG structure of oils in the regiospecific data obtained from the current 13C NMR than that from conventional methods. In the absence of laborious chemical derivatization, this method is simple, accurate, and user‐friendly for researchers, especially for nutritionists to support their nutritional studies from the perspective of positional FAC of edible oils and fats.

Comparative Transcriptome Analysis of Three Oil Palm Fruit and Seed Tissues That Differ in Oil Content and Fatty Acid Composition

“…Finally, no CPT transcript was consistently detected in the endosperm with its very low PUFA percentage. About 75% of mesocarp 18:2 is at the sn-2 position of TAG (Gouk et al, 2012). This proportion is in agreement with an enrichment of TAG in PUFA through PC-DAG interconversion.…”

Nuclear Magnetic Resonance Spectroscopy: A Versatile Tool for Qualitative and Quantitative Analysis of an Emulsifier Mixture of Soybean Oil

“…These data provide information on FA composition of HMMS and the different positions of the esterified chains. The 13 C NMR spectrum of the carbonyl carbons of different oils was used to identify the acyl positional distribution ( sn ‐1,3 vs sn ‐2) of the SFA and UFA groups (Gouk et al, ) and also to provide information on the length and unsaturation pattern of the FA (Vlahov et al, ).…”

Efficient Separation and Analysis of Triacylglycerols: Quantitation of β-Palmitate (OPO) in Oils and Infant Formulas

“…26 A mixture of 1-palmitoyl-2,3-distearoyl-, 1-stearoyl-2-linoleoyl-3-palmitoyl-, 1-linoleoyl-2-stearoyl-3-palmitoyl-, and 1,2-dilinoleoyl-3-palmitoylglycerols was prepared from 1-monopalmitoylglycerol and a mixture of stearic and linoleic acids (1.00:1.03 mol/mol) using the same method. Similarly, a mixture of tristearin, triolein, 1-stearoyl-2,3-dioleoyl-, 1,3-dioleoyl-2-stearoyl-, 1,2-distearoyl-3-oleoyl-, and 1,3-distearoyl-2-oleoylglycerols was prepared from glycerol and a mixture of stearic and oleic acids (1.00:1.00 mol/mol).…”