Multi-frequency large amplitude pulse voltammetric electronic tongue to assess key compounds imparting the taste of briskness to finished black tea liquor

Abstract

In a constant endeavour to improve the quality evaluation methodology of black tea in a rapid and objective manner, electronic tongue has been a promising technology. In this direction, a multi-frequency pulse voltammetric electronic tongue is proposed towards the quantification of specific astringent compounds in tea having direct bearing on tea taste. Twenty tea samples were analysed with a voltammetric electrode array of noble metals, i.e. gold, iridium, palladium, platinum and rhodium. The electronic tongue response has been preprocessed and prediction models have been developed with partial least squares regression (PLSR) technique. The concentrations of simple theaflavin (TF1) and Theaflavin-3'-gallate (TF3) have been estimated from the electronic tongue response. The predictions of electronic tongue are in good agreement with the high performance liquid chromatography (HPLC) based estimations of TF1 and TF3. The electronic tongue predictions have been used to obtain the quality perception of tea in terms of briskness values.