SIMULATION AND APPLICATION OF FUZZY THEORY FOR SUPERCRITICAL CARBON DIOXIDE EXTRACTION OF GREEN TEA

摘要

This study performs a series of experimental investigations to determine the temperature and pressure conditions which maximize the quantities of caffeine and EGCG extracted from green tea using a supercritical fluid extraction process with a carbon dioxide solvent. The experimental data are then used to construct a fuzzy model for predicting the extractant quantities given the temperature and pressure conditions of the extraction process. The average discrepancy between the experimental results and the predicted results for the quantities of caffeine and EGCG extracted at temperatures of 40°C, 50°C and 60°C, respectively, is found to be just 7.38%, thus confirming the viability of the fuzzy model as a predictive tool. Overall, the results reveal that a temperature of 40°C and a pressure of 2500 psi represent the optimum extraction conditions for both caffeine and EGCG.