Measurement of Conjugated Linoleic Acid (CLA) in CLA-Rich Soy Oil by Attenuated Total Reflectance−Fourier Transform Infrared Spectroscopy (ATR−FTIR)

Abstract

Conjugated linoleic acid (CLA) isomers in oils are currently measured as fatty acid methyl esters by a gas chromatography-flame ionization detector (GC-FID) technique, which requires approximately 2 h to complete the analysis. Hence, we aim to develop a method to rapidly determine CLA isomers in CLA-rich soy oil. Soy oil with 0.38-25.11% total CLA was obtained by photo-isomerization of 96 soy oil samples for 24 h. A sample was withdrawn at 30 min intervals with repeated processing using a second batch of oil. Six replicates of GC-FID fatty acid analysis were conducted for each oil sample. The oil samples were scanned using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and the spectrum was collected. Calibration models were developed using partial least-squares (PLS-1) regression using Unscrambler software. Models were validated using a full cross-validation technique and tested using samples that were not included in the calibration sample set. Measured and predicted total CLA, trans,trans CLA isomers, total mono trans CLA isomers, trans-10,cis-12 CLA, trans-9,cis-11 CLA and cis-10,trans-12 CLA, and cis-9,trans-11 CLA had cross-validated coefficients of determinations (R2v) of 0.97, 0.98, 0.97, 0.98, 0.97, and 0.99 and corresponding root-mean-square error of validation (RMSEV) of 1.14, 0.69, 0.27, 0.07, 0.14, and 0.07% CLA, respectively. The ATR-FTIR technique is a rapid and less expensive method for determining CLA isomers in linoleic acid photo-isomerized soy oil than GC-FID.

Rapid three-dimensional structuring of transparent SiO2 glass using interparticle photo-cross-linkable suspensions

“…2e, signals attributed to vibrations of the interior siloxane bonds (1866 cm −1 ) 41 and OH bending vibrations (1630 cm −1 ) of the surface-bound water 41 were found in the raw powder sample. For the SiO 2 particles before UV irradiation, bands correspond to CH 2 scissoring (1462 cm −1 ) were further detected, which originated from OA [42][43][44] and PEI 45 . A small absorbance of the C=O stretching vibration (1732 cm −1 ) from MA 46 was also detected, suggesting the occurrence of the Michael additive reaction between MA and amino groups of PEI-OA bound on the particle surface, at room temperature in slight degree.…”

Effect of fatty acids complexed with polyethyleneimine on the flow curves of TiO2 nanoparticle/toluene suspensions

“…From the FT-IR spectra of the original reagents, signals are observed for the aromatic C C stretching modes (1603 and 1496 cm −1 ), and CH 3 deformation vibration (1460 and 1384 cm −1 ) from toluene [22,23], and N H bending of amines (1600 cm −1 ) and CH 2 scissoring (1462 cm −1 ) from PEI [20,22]. From OA, stretching vibration of hydrogen-bonded C O from COOH (1710 cm −1 ), C O H bending (1418 cm −1 ) and CH 2 scissoring (1462 cm −1 ) can be observed [22,[24][25][26]. The spectra from ISA had adsorption peaks attributed to the stretching vibration of hydrogen-bonded C O from COOH (1710 cm −1 ), C O H bending (1418 cm −1 ), CH 2 deformation (1377 cm −1 ), and CH 2 wagging (1460 cm −1 ) [27].…”

Chemometric Characterization of Sunflower Seeds

“…Multivariate methods have been widely reported for the classification of edible oils, including the classification of genetic varieties of olive oil by HPLC‐MS (Lerma‐García and others 2009); infrared spectroscopy for the authentication of olive oils (Lerma‐García and others 2010) and their geographical origin (Galtier and others 2007; Galtier and others 2008); the voltammetric method for the classification of edible oils (Gambarra‐Neto and others 2009); classification of vegetable oils from their fatty acid content (Brodnjak‐Voncina and others 2005); NMR spectroscopy, for the classification of edible oils and detection in olive oil adulteration, (Vigli and others 2003); classification of vegetable oils by GC‐MS (Jakab and others 2002); thermal degradation of edible oils (Moros and others 2009); adulteration of olive oil by Visible and NIR spectroscopy (Downey and others 2002); determination of linoleic acid by attenuated total reflectance Fourier transform infrared spectroscopy (Kadamne and others 2009); and classification of edible oil using phosphorescence data (Arancibia and others 2008). However, there exist only a few reports that characterize plants and seeds by multivariate data analysis, including pumpkin seeds (Saucedo‐Herna and others 2011), amaranth seeds (Aguilar and others 2011), onion (Galdón and others 2010), maize kernel (Williams and others 2009), green coffee (Alonso‐Salces and others 2009), perilla seeds (Kim and others 2007), corn kernel (Weinstock and others 2006), and soybean (Roberts and others 2006).…”