Semi-quantitative and quantitative analysis of soft drinks using an electronic tongue

Abstract

A potentiometric electronic tongue with 36 cross-sensibility lipo/polymeric membranes was built andapplied for semi-quantitative and quantitative analysis of non-alcoholic beverages. A total of 16 commercialfruit juices (e.g., orange, pineapple, mango and peach) from five different brands were studied.In the semi-quantitative approach, the signal profiles recorded by the device were used together with astepwise linear discriminant analysis to differentiate four beverage groups with different fruit juice contents:>30%, 14-30%, 6-10% and <4%. The model, with two discriminant functions based on the signalsof only four polymeric membranes, explained 99% of the total variability of experimental data and wasable to classify the studied samples into the correct group with an overall sensibility and specificity of100% for the original data, and greater than 93% for the cross-validation procedure.The signals were also used to obtain MLR and PLS calibration models to estimate and predict theconcentrations of fructose and glucose in the soft drinks. The linear models established were based onthe signals recorded by 16 polymeric membranes and were able to estimate and predict satisfactorily(cross-validation) the concentrations of the two sugars (R2 greater than 0.96 and 0.84, respectively).