Sensory intensity assessment of olive oils using an electronic tongue

• Published in: Talanta (Oxford) 2016-01, Vol.146, p.585-593
• Main Authors: Veloso, Ana C.A., Dias, Luís G., Rodrigues, Nuno, Pereira, José A., Peres, António M.
• Format: Article
• Language: English
• Subjects: Algorithms; Biomimetics - instrumentation; Discriminant Analysis; Electrical Equipment and Supplies; Food Quality; Linear discriminant analysis; Olive Oil - chemistry; Phenols - analysis; Potentiometric electronic tongue; Sensory intensity perception classification; Simulated annealing algorithm; Single cultivar extra virgin olive oil; Taste; Tongue
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2015.08.071

Olive oils may be commercialized as intense, medium or light, according to the intensity perception of fruitiness, bitterness and pungency attributes, assessed by a sensory panel. In this work, the capability of an electronic tongue to correctly classify olive oils according to the sensory intensity perception levels was evaluated. Cross-sensitivity and non-specific lipid polymeric membranes were used as sensors. The sensor device was firstly tested using quinine monohydrochloride standard solutions. Mean sensitivities of 14±2 to 25±6mV/decade, depending on the type of plasticizer used in the lipid membranes, were obtained showing the device capability for evaluating bitterness. Then, linear discriminant models based on sub-sets of sensors, selected by a meta-heuristic simulated annealing algorithm, were established enabling to correctly classify 91% of olive oils according to their intensity sensory grade (leave-one-out cross-validation procedure). This capability was further evaluated using a repeated K-fold cross-validation procedure, showing that the electronic tongue allowed an average correct classification of 80% of the olive oils used for internal-validation. So, the electronic tongue can be seen as a taste sensor, allowing differentiating olive oils with different sensory intensities, and could be used as a preliminary, complementary and practical tool for panelists during olive oil sensory analysis. [Display omitted] •EVOO fruitiness, bitterness and pungency sensations evaluated by a sensory panel.•88 Samples from 11 single-cultivar EVOO grouped according to the sensory intensity perception.•EVOO analyzed by a potentiometric E-tongue.•E-tongue potential signals increased with quinine concentration, i.e. to bitterness level.•LDA-SA correctly classified EVOO according to the sensory intensity perception.