Authentication of Tunisian virgin olive oils by chemometric analysis of fatty acid compositions and NIR spectra. Comparison with Maghrebian and French virgin olive oils

Abstract

Six Tunisian virgin olive oil (VOO) varieties, Chemlali Sfax, Chetoui, Chemchali, Oueslati, Zarrazi and Zalmati, were characterised by two analytical methods. The gas chromatography allowed the determination of 14 fatty acids and squalene amounts. With fatty acids of each variety, a characteristic "morphotypes" for each oil variety was established. Chemlali Sfax and Zalmati showed strong similarities. Gas chromatography of fatty acid methyl esters (FAME) and near infrared (NIR) spectra of oils, associated to chemometric treatment, allowed the study of the inter-varietal variability and the verification of the variety origins of some Tunisian commercial VOOs. The specificity of Tunisian VOOs was evaluated by comparing the samples to Algerian, Moroccan and French Protected Designation of Origin VOOs. Classification in varietal origins by SIMCA used the FAME compositions and NIR spectra of the most represented varieties (Chemlali Sfax, Chetoui and Oueslati) showed a high potential to authenticate the varietal origin of Tunisian VOOs.

Comparative Study of Oil Quality and Aroma Profiles from Tunisian Olive Cultivars Growing in Saharian Oasis Using Chemometric Analysis

“…However, the highest amounts of carotenes were observed in the oils of Chemlali and Koroneiki varieties at HD 1 . These results agree with the finding by other authors 10,30 .…”

Pedologic Factors Affecting Virgin Olive Oil Quality of “Chemlali” Olive Trees (<i>Olea europaea</i> L.)

“…The quality criteria depend essentially on the olive quality before the extraction and the storage conditions. Several studies 18 reported that the free acidity increase during ripening while peroxide value and K 232 and K 270 extinction coefficients decrease slightly during ripening. In order to limit the effect of the ripening stage on the studied chemical parameters, sampling was done at the same stage of maturity.…”

Application of an electronic tongue for Tunisian olive oils’ classification according to olive cultivar or physicochemical parameters

“…[1,[5][6][7][8], aiming to set authentication biomarkers that could help minimize the risk of frauds. Some works reported the capability of discriminating EVOO according to the geographical origin (i.e., different regions in the same country or different countries), using different analytical techniques and chemometric tools [4,9,10]. In addition, Hassine et al [11] carried out a chemical and sensorial characterization and preference mapping of autochthonous (Chetoui, Oueslati, Chemlali and Zalmati) and introduced (Arbequina) olive oil cultivars in Tunisia showing that based on those profiles it was possible to differentiate the VOO according to olive variety and geographical origin.…”