A 43 MHz Low-Field Benchtop ¹H Nuclear Magnetic Resonance Method to Discriminate Perilla Oil Authenticity

Abstract

The aim of this study was to discriminate the authenticity of perilla oils distributed in Korea using their H nuclear magnetic resonance (NMR) spectra acquired by a 43 MHz low-field benchtop NMR spectrometer. Significant differences existed in the integration values of all 6 peaks found in the spectrum between authentic and adulterated perilla oil samples. The integration values of 4 peaks that signify the methylene protons present in all fatty acids (FA) and allylic or olefinic protons present in all unsaturated FA were the best variables for establishing perilla oil authenticity. The procedure for applying the range of variables found in authentic perilla oil samples correctly discriminated between the samples of perilla oils with soybean oils added at concentrations of ≥ 6 vol%. The results demonstrated that this NMR procedure is a possible cost-effective alternative to the high-fieldH NMR method for discriminating the authenticity of perilla oils.

NMR-based metabolomics and fluxomics: developments and future prospects

“…Other illustrations of the potential of benchtop NMR metabolomics were reported in the so-called "foodomics" field, such as the discrimination between beef versus horse meat 99 or the detection of adulteration of perilla oil with soybean oil. 100 An application to the quality control of diesel fuel was also recently reported. 101 Although not belonging to metabolomics in the strictest sense of the word, these profiling applications are very interesting, because they illustrate the potential of benchtop NMR to make metabolomics approaches accessible to fields of science and industry where NMR is not traditionally used.…”

Low‐field benchtop NMR spectroscopy: status and prospects in natural product analysis†

“…In contrast, peaks corresponding with ranges 6 and 4 became smaller upon adulteration as these ranges are correlated with double bonds and PUFAs, respectively. Adulteration with ≥ 6% ( v / v ) soybean oil was detectable 29 …”

“…A LF‐NMR method for adulteration detection of Perilla frutescens edible oil with 30 times cheaper soybean oil was developed 29 . Samples (100 μL, in triplicate) were dissolved in 500 μL of CDCl 3 containing 0.03% TMS (tetramethylsilane), measured at 43 MHz and the ranges of 0.5279–1.0454, 1.0643–1.664, 1.6641–2.5532, 2.5720–3.1742, 4.0046–4.5009 and 4.8631–5.8652 ppm were integrated (ranges 1–6).…”

Low‐field NMR for quality control on oils

“…By means of the LF‐NMR measurement of transverse relaxation and subsequent data analysis via calculation of T 2 distributions and principal component analysis, adulterations were detected and quantified. Kim et al could prove the adulteration of perilla oil with soybean oil (>6 vol%), which is widespread in Korea, by low‐field spectroscopy at 43 MHz.…”