Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) Coupled with Chemometrics, to Control the Botanical Authenticity and Quality of Cold-Pressed Functional Oils Commercialized in Romania  
1 Department of Food Science, Faculty of Food Science and Technology, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 400372 Cluj-Napoca, Romania; [EMAIL_ADDRESS] (F.F. ); [EMAIL_ADDRESS] (F.R. ); [EMAIL_ADDRESS] (S.S.)
2 Faculty of Animal Science and Biotechnology, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 400372 Cluj-Napoca, Romania; [EMAIL_ADDRESS]
3 Faculty of Agriculture, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 400372 Cluj-Napoca, Romania; [EMAIL_ADDRESS]
4 Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, 400372 Cluj-Napoca, Romania; [EMAIL_ADDRESS]
5 Correspondence: [EMAIL_ADDRESS]  
[1]  
quality and safety influenced by multiple environmental and technological factors (oxidation, higher levels of trans fatty acids) and adulteration before commercialization. Authenticity is a very important quality criterion for edible oils, considering the significant differences of composition, safety, and price between the cold-pressed (extra virgin, virgin) and refined ones, as well as possible mislabeling of commercial products. Over the past few decades, Fourier transform infrared (FTIR) spectroscopy had provided a reliable analytical tool in the fat and oil industries and become an attractive alternative to traditional methods, being a rapid and easy-to-use technique to evaluate qualitatively or even quantitatively the oils' edibility, their intrinsic quality parameters, safety, as well as authenticity, traceability and adulteration [1; 2; 3; 4; 5; 6; 7]. Moreover, the determination of edible oil authenticity, compared with the more accurate but time-consuming, laborious, and expensive chromatography-based method is advantageous as a more rapid and cheaper solution. Considering the advantages of being non-destructive, cost effective and environmentally friendly, using small amounts of liquid samples and simple preparation procedures [3], FTIR spectroscopy was found to be superior for the discrimination and classification of edible oil comparing to FT-Raman and FT-NIR [8]. The spectral range of the middle infrared region (MIR) of FTIR spectroscopy, from 4000 to 400 cm\({}^{-1}\), has been commonly used for the identification of organic groups, based on their characteristic, fundamental vibrations as well as for the quantitative evaluation of components if adequate calibrations were complemented [9]. The FTIR-MIR spectroscopy with attenuated total reflectance (ATR) or transmission cell accessories has been used to authenticate, identify or classify fats and oils [10; 11; 12; 13], the ATR accessory being a better choice due to its ability to handle easily liquid samples, requiring minimum preparation. It is also an excellent tool for quantitative analysis, because the intensities of the spectral bands are proportional to concentration. It is useful to distinguish oils from different botanical origins using specific wavenumber domains coupled with non-supervised classification techniques [11; 14]. FTIR-ATR spectrometry has been used mainly for (extra) virgin olive oils to distinguish from different genetic varieties [13] and geographical origins [15; 16], meanwhile, the scientific interest for other functional oils showing health benefits is increasing. The applicability of FTIR-MIR spectroscopy in assessing oils fingerprinting and quality parameters is crucially dependent on the chemometric methods, including calibrations with large and representative sample numbers. The chemometric strategies and methods for spectroscopy-based food authentication have been reviewed [17; 18].