Sensory intensity assessment of olive oils using an electronic tongue
Extra virgin olive oil fruitiness, bitterness and pungency sensations evaluated by a sensory panel and then by electronic tongue. This instrument allows 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
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±6 mV/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.
Ana C.A. Veloso, Luís G. Dias, Nuno Rodrigues, José A. Pereira, António M. Peres, Sensory intensity assessment of olive oils using an electronic tongue, Talanta, Available online 1 September 2015, ISSN 0039-9140