Quantification of adulterant agents in extra virgin olive oil by models based on its thermophysical properties

Abstract

Two methods to quantify the adulteration of extra virgin olive oil (EVOO) based on the physical characteristic of adulterated samples have been here described. Firstly, the adulterant agent concentration is determined using the density and/or refractive indices (RIs) of adulterated samples of EVOO with sunflower (SO) or corn (CO) oils by suitable linear correlations between density and/or RI. Finally, models based on the combination of differential scanning calorimetry (DSC) equipment and a chaotic parameter (lag- k autocorrelation coefficients, LCCs) is defined here to quantify adulterations of EVOO with refined olive (ROO), refined olive pomace (ROPO), SO or CO oils. This quantification was carried out using successful linear correlation of LCCs and ROO, ROPO, SO or CO concentrations in 462 adulterated samples of EVOO. The LCCs are calculated from DSC scans of adulterated EVOO samples. In both models studied, the adulterant agent concentrations are less than 14% w/ w. The former is adequate to calculate the concentration of the adulterant agents (CO and SO) with a correlation coefficient ( R 2) higher than 0.927 and mean square error (MSE) lower than 8.9%. By the external validation process, the LCC/DSC approach estimates the adulterant agent concentrations with a R 2 (estimated vs. real adulterant agent concentration) greater than 0.921 and a MSE less than 4.9%.