Combined Analysis of Stable Isotope, H-1 NMR, and Fatty Acid To Verify Sesame Oil Authenticity

Abstract

The aim of this study was to verify the authenticity of sesame oils using combined analysis of stable isotope ratio, H-1 NMR spectroscopy, and fatty acid profiles of the oils. Analytical data were obtained from 35 samples of authentic sesame oils and 29 samples of adulterated sesame oils currently distributed in Korea. The orthogonal projection to latent structure discriminant analysis technique was used to select variables that most effectively verify the sesame oil authenticity. The variables include delta C-13 value, integration values of NMR peaks that signify the CH3 of n-3 fatty acids, CH2 between two C=C, protons from sesamin/sesamolin, and 18:1n-9, 18:3n-3, 18:2t, and 18:3t content values. The authenticity of 65 of 70 blind samples was correctly verified by applying the range of the eight variables found in the authentic sesame oil samples, suggesting that triple analysis is a useful approach to verify sesame oil authenticity.