Changes in thearubigin fractions and theaflavin levels due to variations in processing conditions and their influence on black tea liquor brightness and total colour

Abstract

Increase in coarser plucking standards significantly (P< 0.05) depressed levels of theaflavin (TF; μmol/g), total colour and brightness (spectrophotometer) of black tea. But total thearubigins (TR) TRSI, TRSII and brightness (taster) levels did not significantly (P< 0.05) change with plucking standards. Increasing fermentation duration led to rise in TF (μmol/g), total TR, total colour, TRSI and TRSII, liquor brightness (taster) but not liquor brightness determined by spectrophotometer method (P< 0.05). Correlation analysis showed that total TR and TRSII had negative correlations (r=− 0.66 and− 0.77, P< 0.01), respectively, while total TF levels had positive correlation with taster brightness (r= 0.57, P< 0.01). Total TF level had highest correlation with spectrophotometer liquor brightness (r= 0.87, P< 0.01) for a single substance. TRSII and total TR gave an r of 0.86 indicating that the two groups of …