Quartz crystal microbalance sensors for discrimination of black tea

Abstract

The quality evaluation of black tea is based on organoleptic methods of “Tea- tasters”. However the present quality estimation involving Tea-tasters is not a very reliable method as professional acumen, mood and other personal factors affect the judgment of tea quality. Electronic nose consists of an array of gas sensors with overlapping selectivity patterns, signal handling and classifier modules. An array of quartz crystal microbalance (QCM) sensors has been developed to differentiate among different tea samples. The important volatile components responsible for aroma of tea have been considered and the corresponding sensing materials have been identified. Five AT-cut 10 MHz Quartz crystal blanks coated with different sensing materials have been used to differentiate the aroma of orthodox and cut-tear-curl (CTC) tea samples. The developed sensors can distinguish not only between the orthodox and CTC tea but distinct clusters are also obtained for the four different tea-samples, as visualized through principal component analysis (PCA).