Development of potentiometric electronic tongue to identify adulteration of olive pomace oil in extra virgin olive oil

A lab-made potentiometric electronic tongue (e-tongue) was developed to assess quality and adulteration of olive oil. The e-tongue working electrode were consisted of 28 various membranes lipid/polymer coated directly on gold electrodes. Basically, each membrane generates unique potential which depends on the sample being tested. Several samples of extra-virgin olive oil (EVOO), virgin olive oil (VOO), and pomace olive oil (POO) from different brands were analyzed. Using linear discriminant analysis (LDA) from the measured raw signal of the e-tongue, the result indicates that the first discriminant function of the LDA shows clear separation to differentiate olive oils based on its quality. Quantitative analysis of adulteration in EVOO by POO was conducted using multiple linear regression (MLR) model. Linear regression analysis was established to evaluate the predictive performance established by the MLR model, which provide R2 and RMSE of 0.9988 and 0.4822, respectively. The fact that classification and predictive performance of the e-tongue provide a satisfactory result indicates that the e-tongue is a promising tool for assessment of quality and adulteration in olive oil products.