title: The effect of thermal treatment on the enhancement of detection of adulteration in extra virgin olive oils by synchronous fluorescence spectroscopy and chemometric analysis.
abstract: In this study the effect of thermal treatment on the enhancement of synchronous fluorescence spectroscopic method for discrimination and quantification of pure extra virgin olive oil (EVOO) samples from EVOO samples adulterated with refined oil was investigated. Two groups of samples were used. One group was analyzed at room temperature (25 °C) and the other group was thermally treated in a thermostatic water bath at 75 °C for 8h, in contact with air and with light exposure, to favor oxidation. All the samples were then measured with synchronous fluorescence spectroscopy. Synchronous fluorescence spectra were acquired by varying the wavelength in the region from 250 to 720 nm at 20 nm wavelength differential interval of excitation and emission. Pure and adulterated olive oils were discriminated by using partial least-squares discriminant analysis (PLS-DA). It was found that the best PLS-DA models were those built with the difference spectra (75 °C-25 °C), which were able to discriminate pure from adulterated oils at a 2% level of adulteration of refined olive oils. Furthermore, PLS regression models were also built to quantify the level of adulteration. Again, the best model was the one built with the difference spectra, with a prediction error of 3.18% of adulteration.
authors.affiliation: Department of Biological Sciences & Chemistry, College of Arts and Sciences, University of Nizwa, Oman. Electronic address: mehboob@unizwa.edu.om.
authors.forename: F
authors.initials: F
authors.lastname: Mabood
authors.affiliation: Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Tarragona, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Boqué
authors.affiliation: Department of Chemistry, University of Rome "Sapienza", P.e Aldo Moro 5, I-00185 Rome, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Folcarelli
authors.affiliation: Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Tarragona, Spain.
authors.forename: O
authors.initials: O
authors.lastname: Busto
authors.affiliation: Department of Chemistry, University of Malakand, KPK, Pakistan.
authors.forename: F
authors.initials: F
authors.lastname: Jabeen
authors.affiliation: UoN Chair of Oman Medicinal Plants and Marine Products, University of Nizwa, Sultanate of Oman.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Al-Harrasi
authors.affiliation: Department of Biological Sciences & Chemistry, College of Arts and Sciences, University of Nizwa, Oman.
authors.forename: J
authors.initials: J
authors.lastname: Hussain
mesh_terms: D016002:Discriminant Analysis; D005506:Food Contamination / Q000032:analysis*; D006358:Hot Temperature; D016018:Least-Squares Analysis; D000069463:Olive Oil / Q000032:analysis*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D000069463:Olive Oil
keywords: Adulteration; Extra virgin olive oil (EVOO); PLS regression; PLS-DA; Refined olive oil; Synchronous fluorescence spectroscopy; Thermal treatment