A comparative study of mid-infrared, UV–Visible and fluorescence spectroscopy in combination with chemometrics for the detection of adulteration of fresh olive oils with old olive oils. (November 2019)

• Record Type: Journal Article
• Authors: Uncu, Oguz; Ozen, Banu
• Is Part Of: Food control. Volume 105(2019)
• Page Start: 209
• Page End: 218
• Publication Date: 2019-11
• Subjects: Olive oil -- Adulteration -- FT-IR spectroscopy -- UV–vis spectroscopy -- Fluorescence spectroscopy -- Chemometrics; Food -- Quality -- Periodicals; Food -- Analysis -- Periodicals; Food handling -- Periodicals; Food industry and trade -- Quality control -- Periodicals; Aliments -- Industrie et commerce -- Qualité -- Contrôle -- Périodiques; Aliments -- Qualité -- Périodiques; Aliments -- Analyse -- Périodiques; Hygiène alimentaire -- Périodiques; Food -- Analysis; Food handling; Food -- Quality; Periodicals; Electronic journals; 664.07
• DOI: 10.1016/j.foodcont.2019.06.013
• Languages: English
• ISSNs: 0956-7135

Abstract

Abstract: The work aimed to detect and quantify adulteration of fresh olive oils with old olive oils from the previous harvest year by using different spectroscopic approaches in combination with chemometrics. Adulterated samples prepared in varying concentrations (10-50%(v/v)) were analyzed with fluorescence, Fourier transform-infrared (FT-IR), and ultraviolet–visible (UV–vis) spectroscopic methods. Orthogonal partial least square-discriminant analysis (OPLS-DA) and partial least squares (PLS) regression techniques were used for the differentiation of adulterated oils from the pure oils and prediction of adulteration levels, respectively. After the application of various pre-treatment methods, all of the OPLS-DA classification models generated for every spectroscopic technique successfully differentiated adulterated and non-adulterated oils with over 90% correct classification rate. FT-IR + UV–vis and fluorescence spectral data were also successfully used to predict adulteration levels with high coefficient of determinations for both calibration (0.94 and 0.98) and prediction (0.91 and 0.97) models and low error values for calibration (4.22% and 2.68%), and prediction (5.20% and 2.82%), compared to individual FT-IR and UV–vis spectroscopy were obtained. Therefore, FT-IR + UV–vis and fluorescence spectroscopy as being fast and environmentally friendly tools have great potential for both classification and quantification of adulteration practices involving old olive oil. Highlights: Adulteration of fresh olive oils with old olive oils was investigated. Different spectroscopic approaches were used to detect adulteration. Fluorescence and FTIR + UV–vis spectroscopies were successful to predict adulteration. Prediction error for adulterant level was low enough (<10%) for both approaches. Spectroscopic data allow simultaneous detection and quantification of adulteration.