Investigations on sensorial properties of indian black teas using impedance based techniques

Abstract

Multi-electrode Impedance technique is proposed for discrimination of Indian black tea.Impedance response of platinum, gold, silver, glassy carbon, polyaniline and polypyrrole working electrodes in tea infusions for a sinusoidal excitation in the frequency range of 1Hz to 100kHz has been measured.Also,the percentage of major chemical constituents responsible for the tea quality has been determined by HPLC and UV vis spectrophotometer.Frequency specific impedance response of these working electrodes along with the determined chemical concentrations was subjected to Principal Component Analysis to confirm the discriminability of the proposed impedance technique.The correlations between the frequency specific impedance response of working electrodes and the chemical concentrations which depend on sample variability,such as harvest interval,manufacturing process and brand type have been established.