New 'electronic tongue' system assesses the antioxidant power of juices and fruit

According to the UPV researchers, in recent years, electronic tongues have become an excellent alternative to traditional methods of analysis for controlling the quality of food products. "Electronic tongues, using electrochemical techniques, help us to sort food samples in situ and to quantify their physicochemical parameters, in a fast and economical way," said Ramón Martínez Máñez, a researcher at the UPV IDM.

The electronic tongue system designed by UPV researchers is based on techniques of voltammetry and impedance spectroscopy, and consists of a PC application and some electronic measuring equipment. In addition, the software that they have developed allows not only to perform tests but to store the data corresponding to the measurements obtained as well.

So far, UPV experts have tested the usefulness of this system in different antioxidant solutions -specifically, citric acid, ascorbic acid (vitamin C) and malic acid, and binary mixtures of those-, and the results have been highly satisfactory.

"What we do is, we apply electrical signals to the solution and we measure its response. Thus we can quantify the antioxidant concentration in that solution," said Miguel Alcañiz, IDM researcher at the Universitat Politècnica de València.

Now, researchers at the IDM and the Group of CUINA Politècnica de València are working on the study of the degradation of vitamin C in juices. "We're starting to work very soon in the direct application of the electronic tongue to the evaluation of orange juice," said José Manuel Barat, a researcher at the UPV's CUINA group.

UPV researchers have also studied the application at the laboratory of this electronic tongue system to the detection of glyphosate, a weedkiller which is widely used in agriculture, and to monitoring water quality in sewage treatment plants.

This system has been presented within the framework of the V Workshop on Sensors and Molecular Recognition, organized by IDM, which took place recently at the UPV's School of Agricultural Engineering and Environment.

New 'electronic tongue' system assesses the antioxidant power of juices and fruit