Quantitative determination of the iodine values of unsaturated plant oils using infrared and Raman spectroscopy methods |
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| Authors: | Lucyna Dymińska Maciej Calik Abduladhim Moamer M. Albegar Adam Zając Kamil Kostyń Jadwiga Lorenc |
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| Affiliation: | 1. Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Faculty of Engineering and Economics, Wroc?aw University of Economics, Wroc?aw, Polandlucyna.dyminska@ue.wroc.pl;3. Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Faculty of Engineering and Economics, Wroc?aw University of Economics, Wroc?aw, Poland;4. Faculty of Agriculture, Azzaytuna University, Azzaytuna, Libya;5. Faculty of Biotechnology Sciences, Wroc?aw University, Przybyszewskiego, Poland |
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| Abstract: | Thirteen edible oils: sunflower, avocado, hemp, high-linolenic flax, low-linolenic flax, safflower, walnut, roasted sesame, rice, corn, rapeseed, pumpkin seed, and hazel were studied in this work. Their fatty acid composition, iodine, acidic, peroxide, and saponification values were determined. Infrared and Raman spectra of the oils were recorded in the range 400–3200 cm?1. The integral intensities of the bands at about 1655 and 2852 cm?1 corresponding to ν(C=C) and ν(CH2) vibrations were evaluated and used to construct a relationship between the spectroscopic data and the iodine value. The following linear dependencies were obtained: Iν(C=C)/Iν(CH2) = 7.449 × 10?4 × iodine value – 0.0339 and Iν(C=C)/Iν(CH2) = 9.299 × 10?4 × iodine value – 0.023 for the infrared and Raman spectra with a correlation coefficient 0.988 and 0.976, respectively. These calibration lines can be used to determine the iodine value for oils with unknown unsaturation level, and may be applied for margarines and other fatty materials. |
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| Keywords: | Plant oils Infrared and Raman spectra Lorentz deconvolution Iodine value Quantitative analysis of unsaturation degree |
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