Percorrer por autor "Souayah, Fatma"
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- Classification of single-cultivar Tunisian olive oils according to the geographical origin using an electronic tonguePublication . Souayah, Fatma; Rodrigues, Nuno; Veloso, Ana C.A.; Dias, L.G.; Oueslati, Souheib; Pereira, J.A.; Peres, António M.The marketing of olive oil is focused to a greater extend on the distinction and characterization of products according to their geographical origins. Due to the great impact of geographic, agronomic and technological factors on the physicochemical quality of olive oils, it is important to be able to discriminate them according to their geographical origins in order to avoid or minimize the risk of frauds. In this work, it was intended to verify the capability of an electronic tongue to classify monovarietal Tunisian olive oils (cvs Chemlali or Sahli) according to geographical origins (i.e. Tunisian districts). For this purpose, chemometric tools were applied in order to establish linear discriminant models based on selected sub-sets of potentiometric signals profiles gathered with the electronic tongue. In this research, 30 samples belonging to the two above-mentioned varieties were analyzed by the electronic tongue additionally to legally required physicochemical analysis, which included the free acidity, the peroxide value and the coefficients of extinction K232, K270 and t::.K. These olive oil samples were grouped according to 3 regions for the Chemlali variety (i.e. Kairouan, Sidi Bouzid and Sfax- Center Tunisia) and 3 regions as well for the Sahli variety (i.e. Mahdia, Sousse and Kairouan - North and Center Tunisia). Preliminary results showed that it was possible to classify Tunisian olive oisl according to the geographical region with a minimum correct classification rate of 94% for cross-validation procedure. These findings pointed out the potential use of the electronic tongue as an efficient and low-cost analytical technique for classifying the Tunisian autochthonous monovarietal olive oils according to their geographical origin.
- Classification of single-cultivar Tunisian olive oils according to the geographical origin using an electronic tonguePublication . Souayah, Fatma; Rodrigues, Nuno; Veloso, Ana C.A.; Dias, L.G.; Oueslati, Souheib; Pereira, J.A.; Peres, António M.Developing analytical techniques for EVOO authentication is a challenging task. Moreover, if a specific meteorological or geographical factor affects different geographical regions similarly, olive oils' geographical discrimination may be a hard task. Improved classification of olive oils may be achieved by combining electrochemical fingerprints with multivariate statistical techniques. In this work, we used an electronic tongue, comprising 40 lipid membrane sensors, to extract suitable potentiometric fingerprints of Tunisian monovarietal olive oils that could be used in combination with linear discriminant analysis to classify olive oils according to the geographical origin.
- Discrimination of olive oil by cultivar, geographical origin and quality using potentiometric electronic tongue fingerprintsPublication . Souayah, Fatma; Rodrigues, Nuno; Veloso, Ana C.A.; Dias, L.G.; Pereira, J.A.; Oueslati, Souheib; Peres, António M.Legal regulations are set for protecting claims regarding olive oil geographical denomination. When meteorological or agroecological factors similarly affect different regions, the origin identification is a challenging task. This study demonstrated the use of a potentiometric electronic tongue coupled with linear discriminant analysis to discriminate the geographical origin of monovarietal Tunisian olive oil produced from local cv Chemlali (Kairouan, Sidi Bouzid or Sfax regions) and cv Sahli (Kairouan, Mahdia or Sousse regions). The potentiometric fingerprints of 12 or eight lipid sensors (for Chemlali and Sahli, respectively), selected using a simulated annealing meta-heuristic algorithm, allowed the correct prediction (repeated K-fold cross-validation) of the geographic production region with sensitivities of 92 ± 7% (Chemlali) and 97 ± 8% (Sahli). It was also confirmed the electronic tongue capability to classify Tunisian olive oil according to olive cultivar or quality grade. The results indicated the possible use of potentiometric fingerprints as a promising innovative strategy for olive oil analysis allowing assessing geographical origin, olive cultivar and quality grade, which are key factors determining olive oil price and consumers’ preference.
- Tunisian olive oils geographical origin discrimination using the potentiometric fingerprints recorded by an electronic tonguePublication . Veloso, Ana C.A.; Souayah, Fatma; Rodrigues, Nuno; Dias, L.G.; Oueslati, Souheib; Pereira, J.A.; Peres, António M.The development of fast and cost-effective analytical techniques for EVOO authentication is a challenging task. Moreover, if a specific meteorological or geographical factor affects different geographical regions similarly, olive oils geographical discrimination may be a hard task using conventional analytical techniques [1]. E-noses and/or voltammetric E-tongues have already been applied to assess olive oils' geographical origin, mainly to discriminate different countries or quite different regions of the same country [2]. In this work, we used an electronic tongue (E-tongue ), with 40 lipid membrane sensors, to extract representative potentiometric fingerprints of Tunisian monovarietal olive oils that, in combination with linear discriminant analysis (LOA), could be used to classify olive oils according to the geographical origin. Aqueous ethanolic (80:20, v/v) extracts of different single-cultivar Tunisian olive oils were electrochemically analysed. According to the literature [3-6], these olive oil' extracts are rich in polar compounds that deliver different overall potentiometric responses, which can then be used to evaluate the E-tongue performance for olive oils geographical origin discrimination. The proposed E-tongue-LDA approach, based on the signal profiles of different sub-sets of sensors (seleted with the simulated annealing meta-heuristic algorithm) allowed the correct geographical origin classification of Tunisian olive oils produced from autochthonous Chemleli or Sahli cultivars (i.e., Kairouan, Sidi Bouzid and Sfax; or, Mahdia, Sousse and Kairouan; respectively). Indeed, predictive correct classifications of 92±7% and 97±8% (for repeated K-fold cross-validation) could be obtained for Chemleli or Sahli olive oils, pointing out the potential use of the E-tongue device for geographical origin identification of olive oils.
- Tunisian olive oils geographical origin discrimination using the potentiometric fingerprints recorded by an electronic tonguePublication . Veloso, Ana C.A.; Souayah, Fatma; Rodrigues, Nuno; Dias, L.G.; Oueslati, Souheib; Pereira, J.A.; Peres, António M.The development of fast and cost-effective analytical techniques for EVOO authentication is a challenging task. Moreover, if a specific meteorological or geographical factor affects different geographical regions similarly, olive oils geographical discrimination may be a hard task using conventional analytical techniques [1]. E-noses and/or voltammetric E-tongues have already been applied to assess olive oils' geographical origin, mainly to discriminate different countries or quite different regions of the same country [2].