Abstract
[Display omitted]
•Sequential SFE of caffeine and catechins from tea samples were optimized.•Pressure, temperature, extraction period and modifier flow rate were determined.•Optimized method was applied to waste tea materials.•Analysis of tea catechins was carried out by HPLC.
The present study investigated the sequential extraction of caffeine and catechins from green tea biomass using an optimized SFE method. The SFE of caffeine was carried out at different pressure (10, 20, 25, 30MPa), temperature (30, 40, 50, 60°C) and extraction periods (1, 2, 3, 5h) for 10g sample. Caffeine extract yields and purity were optimized for a successful separation. Optimum conditions for caffeine extraction were 25MPa pressure at 60°C for 3h extraction period. Following this the same sample was extracted in the presence of ethanol as modifier. The highest catechin extract yield was obtained at 25MPa pressure and 60°C temperature for 3h extraction period using ethanol modifier at 0.5mL/min flow rate. The purity and quantitative amount of each catechin derivatives were determined with a validated HPLC-DAD analysis. Optimized method was employed for selective extraction of tea waste biomaterials.