Kinetic modeling of pressure-assisted solvent extraction of polyphenols from green tea in comparison with the conventional extraction

In the study, the kinetics of pressure-assisted solvent extraction (PSE) of polyphenols from green tea at different pressures (300, 400, 500 MPa) was studied. The model derived from Patricelli, which describes the two step extraction consisting of rapid washing followed by slow diffusion, had been applied to estimate the extraction kinetics. The model parameters were calculated using the experimental results obtained from PSE and conventional solvent extraction (CSE). The results showed a good prediction of Patricelli's model for extraction kinetics in all experiments (R2 ⩾ 0.996), which gave the possibility for estimation of the extraction rate and extent of PSE. The results also showed that the extraction by washing was more efficient with PSE than CSE. In addition, the initial extraction rate of the PSE was always much larger than that of the CSE. Therefore, PSE was more effective for extracting the green tea polyphenols than the CSE.