Implementation of a portable electronic tongue system for detection of sodium benzoate adulteration in tomato paste

< p >Tomato paste is one of the most important flavorings in food, so monitoring the quality and safety of food in this highly-consumed product is drastically important. In this study, a portable electronic tongue system including an array of electrochemical sensors based on graphite pencil electrodes was implemented to detect sodium benzoate adulteration in tomato paste. To adulterate the tomato paste, different values of sodium benzoate (20, 60, and 100 microliters) were added to the natural tomato paste free of sodium benzoate. In the measurement process, a cyclic voltammetric technique with a potential range of 0 to 1 volt was used to detect sodium benzoate. The results showed that pH = 7 was optimal for phosphate buffer, used to detect sodium benzoate. Graphene also performed the best results as a modifier for the electrode surface of the graphite pencil to detect the amount of sodium benzoate in comparison with two other modifiers such as gold nanoparticles and magnetic nanoparticles. The results obtained by classifying the samples demonstrated the high capability of the electronic tongue system for detection of sodium benzoate adulteration in tomato paste. According to the results, the three-electrode sensor system used in this study, including graphite pencil, silver / silver chloride reference and auxiliary platinum electrodes, is efficient in detection of sodium benzoate in tomato paste.