The influence of processing conditions on catechin, caffeine and chlorophyll contents of green tea (Camelia sinensis) leaves and infusions

Green tea samples were produced from different roasting temperatures (200 and 300 degrees C) and drying temperature (80, 120 and 160 degrees C). Individual catechins, total catechins, caffeine, and chlorophylls content were all evaluated in dried green tea leaves and green tea infusions. The color of dried tea leaves and tea infusions were also evaluated. Results showed variation of individual catechins, total catechins, caffeine, and chlorophylls content among both the dried tea leaves and of the tea infusions. Epimerization and thermal degradation were reported to be the main cause of change in tea catechins during processing. A correlation analysis indicated that total catechins content in dried tea leaves had significant effect with the content in tea infusions. Chlorophyll was considered an important compound for determining the greenness of dried tea leaves, but it had no impact on the color of the tea infusions. Results from this study suggest that strict temperature control is important for maintaining chemical constituents in green tea.