title: Application of lag-k autocorrelation coefficient and the TGA signals approach to detecting and quantifying adulterations of extra virgin olive oil with inferior edible oils.
abstract: The combination of lag-k autocorrelation coefficients (LCCs) and thermogravimetric analyzer (TGA) equipment is defined here as a tool to detect and quantify adulterations of extra virgin olive oil (EVOO) with refined olive (ROO), refined olive pomace (ROPO), sunflower (SO) or corn (CO) oils, when the adulterating agents concentration are less than 14%. The LCC is calculated from TGA scans of adulterated EVOO samples. Then, the standardized skewness of this coefficient has been applied to classify pure and adulterated samples of EVOO. In addition, this chaotic parameter has also been used to quantify the concentration of adulterant agents, by using successful linear correlation of LCCs and ROO, ROPO, SO or CO in 462 EVOO adulterated samples. In the case of detection, more than 82% of adulterated samples have been correctly classified. In the case of quantification of adulterant concentration, by an external validation process, the LCC/TGA approach estimates the adulterant agents concentration with a mean correlation coefficient (estimated versus real adulterant agent concentration) greater than 0.90 and a mean square error less than 4.9%.
authors.affiliation: Department of Chemical Engineering, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid, Spain. jstorre@quim.ucm.es
authors.forename: José S
authors.initials: JS
authors.lastname: Torrecilla
authors.forename: Julián
authors.initials: J
authors.lastname: García
authors.forename: Silvia
authors.initials: S
authors.lastname: García
authors.forename: Francisco
authors.initials: F
authors.lastname: Rodríguez
mesh_terms: D000465:Algorithms; D002623:Chemistry Techniques, Analytical; D003314:Corn Oil / Q000032:analysis; D005504:Food Analysis / Q000379:methods; D016014:Linear Models; D000069463:Olive Oil; D010938:Plant Oils / Q000032:analysis*; D000074242:Sunflower Oil; D013818:Thermogravimetry / Q000295:instrumentation*
chemical_list: D000069463:Olive Oil; D010938:Plant Oils; D000074242:Sunflower Oil; D003314:Corn Oil