Determination of three quality parameters in vegetable oils using potentiometric e-tongue

Application of an electronic tongue as a single-run tool for olive oils’ physicochemical and sensory simultaneous assessment

“…3) enabled concluding that the proposed MLRM-SA-E-tongue model allowed quantifying the PV with similar analytical accuracy as that achieved with the official titration technique (the slope and intercept values of the LR of the E-tongue predicted data versus the titration experimental values could be considered equal to one and zero, from a statistical point of view [43,44]). This satisfactory performance is in accordance with the results reported by Rodrigues et al [20] and Semenov et al [28], which also successfully used potentiometric E-tongues for assessing the PV of EVOO during storage or of vegetable oils (including olive oils), respectively.…”

“…3) confirmed the possibility of using a MRLM-SA-E-tongue model, based on signal profiles of 12 sensors, for predicting the TP contents of olive oils from different olive cultivars (repeated K-fold-CV: R 2 = 0.92 ± 0.07; RMSE = 22 ± 8 mg CAE/kg of olive oil). The quality of the results indicates that the E-tongue-based procedure had, from a statistical point of view, a similar accuracy compared to the HPLC conventional method, confirming the reported successful performance of these type of potentiometric devices for TP evaluation [18,28]. Furthermore, the potentiometric E-tongue predictive performance was comparable to that achieved with voltammetric E-tongues, described in the literature [11,14,15].…”

“…This evaluation is of major relevance since polar phenols are related with beneficial health and sensorial properties, while also contributing for olive oil resistance to oxidation. Previous works have reported the successful use of potentiometric E-tongues for assessing the TP levels in Arbequina olive oils [18] and on vegetable oils [28]. So, the capability of the novel potentiometric E-tongue device was also studied for this specific application.…”

“…Tocopherols are non-polar phenols, which also contribute to several of the beneficial nutritional and health effects related to the olive oil consumption and olive oil stability, due to their antioxidant activity. Olive oil extraction using hydroethanolic solutions (water: ethanol, 80:20, v/v) would promote the extraction of polar compounds from the oil, Semenov et al [28], showed that it was possible to satisfactorily determine the total tocopherols (TT) contents of vegetable oils by analysing their water-isopropyl alcohol extracts. Indeed, the presence of small alcohol amounts increases tocopherols solubility due to nonpolar attractive interactions with the alcohol, being the tocopherol concentrations in the hydroalcoholic phase in a relative equilibrium to that of the olive oil [40], and therefore potentially enabling quantification.…”

“…A tentative explanation would be that most of these works reported qualitative approaches, which although quite relevant, do not allow a straightforward assessment, in a quantitative manner, of the olive oil chemical composition neither of its physicochemical or sensory quality, therefore not fully disabling the need for chemical analysis. Indeed, Semenov et al [28] pointed out recently the need to further explore the capacity of these electrochemical devices, namely the potentiometric ones, for the quantitative evaluation of particular chemical olive oil quality parameters. Besides, the possibility of using such electrochemical devices for establishing both physicochemical and sensory profiles based on a single-assay, which would be of utmost practical and economical relevance for olive oil producers and consumers, has not yet been evaluated.…”