Pressurized liquid extraction of caffeine and catechins from green tea leaves using ethyl lactate, water and ethyl lactate plus water mixtures

摘要

Ethyl-lactate (ethyl 2-hydroxy-propanoate) is a bio-renewable agrochemical solvent, very suitable and environmental benign for food applications, permitted by the U.S. Food and Drug Administration as pharmaceutical and food additive. In previous work, the authors demonstrated that pressurized liquid extraction (PLE) using ethyl lactate is a suitable alternative to remove caffeine from vegetal materials, e.g. green coffee beans and green tea leaves. The solubility of caffeine in ethyl lactate + water mixtures, at ambient temperature and pressure, exhibits a substantial increase for 60:40% ethyl lactate + water mixtures (data reported in this work). This result motivated the analysis of the effect of the ethyl lactate + water mixtures for the decaffeination target.