Optimization of sequential supercritical fluid extraction (SFE) of caffeine and catechins from green tea

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, 30 MPa), temperature (30, 40, 50, 60 degrees C) and extraction periods (1, 2, 3, 5 h) for 10 g sample. Caffeine extract yields and purity were optimized for a successful separation. Optimum conditions for caffeine extraction were 25 MPa pressure at 60 degrees C for 3 h extraction period. Following this the same sample was extracted in the presence of ethanol as modifier. The highest catechin extract yield was obtained at 25 MPa pressure and 60 degrees C temperature for 3 h extraction period using ethanol modifier at 0.5 mL/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.