title: Spectroscopic and Chemometric Analysis of Binary and Ternary Edible Oil Mixtures: Qualitative and Quantitative Study.
abstract: The aim of this study was to investigate the feasibility of FTIR-ATR spectroscopy coupled with the multivariate numerical methodology for qualitative and quantitative analysis of binary and ternary edible oil mixtures. Four pure oils (extra virgin olive oil, high oleic sunflower oil, rapeseed oil, and sunflower oil), as well as their 54 binary and 108 ternary mixtures, were analyzed using FTIR-ATR spectroscopy in combination with principal component and discriminant analysis, partial least-squares, and principal component regression. It was found that the composition of all 166 samples can be excellently represented using only the first three principal components describing 98.29% of total variance in the selected spectral range (3035-2989, 1170-1140, 1120-1100, 1093-1047, and 930-890 cm(-1)). Factor scores in 3D space spanned by these three principal components form a tetrahedral-like arrangement: pure oils being at the vertices, binary mixtures at the edges, and ternary mixtures on the faces of a tetrahedron. To confirm the validity of results, we applied several cross-validation methods. Quantitative analysis was performed by minimization of root-mean-square error of cross-validation values regarding the spectral range, derivative order, and choice of method (partial least-squares or principal component regression), which resulted in excellent predictions for test sets (R(2) > 0.99 in all cases). Additionally, experimentally more demanding gas chromatography analysis of fatty acid content was carried out for all specimens, confirming the results obtained by FTIR-ATR coupled with principal component analysis. However, FTIR-ATR provided a considerably better model for prediction of mixture composition than gas chromatography, especially for high oleic sunflower oil.
authors.affiliation: Department of Chemistry, University of Zagreb Faculty of Science , Horvatovac 102a, HR-10000 Zagreb, Croatia.
authors.forename: Ozren
authors.initials: O
authors.lastname: Jović
authors.affiliation: Agrokor d.d., Research and Development Department, Trg Dražena Petrovića 3, HR-10000 Zagreb, Croatia.
authors.forename: Tomislav
authors.initials: T
authors.lastname: Smolić
authors.affiliation: Department of Chemistry, University of Zagreb Faculty of Science , Horvatovac 102a, HR-10000 Zagreb, Croatia.
authors.forename: Ines
authors.initials: I
authors.lastname: Primožič
authors.affiliation: Department of Chemistry, University of Zagreb Faculty of Science , Horvatovac 102a, HR-10000 Zagreb, Croatia.
authors.forename: Tomica
authors.initials: T
authors.lastname: Hrenar
mesh_terms: D016002:Discriminant Analysis; D018625:Microscopy, Atomic Force; D010938:Plant Oils / Q000032:analysis* / Q000737:chemistry*; D025341:Principal Component Analysis; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D010938:Plant Oils