A new method for rapid detection of Total Colour (TC), Theaflavins (TF), thearubigins (TR) and Brightness (TB) in orthodox teas

Theaflavins (TF) and thearubigins (TR) are the important chemical compounds, which contribute to the colour and brightness of tea liquor. Estimation of TF and TR in black tea is generally done using a spectrophotometer. But, the analysis technique undergoes rigorous time consuming effort for sample preparation; also the operation of costly spectrophotometer requires expert manpower. To overcome above problems an electronic vision system (E-Vision system) based on image processing has been developed, which is faster, low cost, repeatable and can estimate the amount of Total Colour (TC), Brightness (TB), Theaflavins (TF) and TF/TR ratio for orthodox tea liquors. This paper describes the newly developed E-Vision system, experimental methods using orthodox black tea sample, data analysis algorithms and finally, the performance of the E-Vision system as compared to the results of traditional spectrophotometer. The data analysis is done using Principal Component Analysis (PCA) and Multiple Linear Regression (MLR). A correlation has been established between colour of tea liquor images and TC, TB, TR and TF/TR ratio.