A composite sensor array impedentiometric electronic tongue Part II. Discrimination of basic tastes.
An impedentiometric electronic tongue based on the combination of a composite sensor array and chemometric techniques aimed at the discrimination of soluble compounds able to elicit different gustative perceptions is presented. A composite array consisting of chemo-sensitive layers based on carbon nanotubes or carbon black dispersed in polymeric matrices and doped polythiophenes was used. The electrical impedance of the sensor array was measured at a frequency of 150 Hz by means of an impedance meter. The experimental set-up was designed in order to allow the automatic selection of a test solution and dipping of the sensor array following a dedicated measurement protocol. Measurements were carried out on 15 different solutions eliciting 5 different tastes (sodium chloride, citric acid, glucose, glutamic acid and sodium dehydrocholate for salty, sour, sweet, umami and bitter, respectively) at 3 concentration levels comprising the human perceptive range. In order to avoid over-fitting, more than 100 repetitions for each sample were carried in a 4-month period. Principal component analysis (PCA) was used to detect and remove outliers. Classification was performed by linear discriminant analysis (LDA). A fairly good degree of discrimination was obtained.
Pioggia
G
G
Interdepartmental Research Center "E. Piaggio", Faculty of Engineering, University of Pisa, Italy. giovanni.pioggia@ing.unipi.it <giovanni.pioggia@ing.unipi.it>
Di Francesco
F
F
Marchetti
A
A
Ferro
M
M
Leardi
R
R
Ahluwalia
A
A
D001185:Artificial Intelligence; D040761:Biomimetic Materials; D015374:Biosensing Techniques / Q000295:instrumentation*; D016002:Discriminant Analysis; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004581:Electronics; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation* / Q000379:methods; D010363:Pattern Recognition, Automated / Q000379:methods*; D018511:Systems Integration; D013649:Taste; D014059:Tongue; D014159:Transducers