Selection of caffeine adsorbent and the optimization of adsorption process of caffeine in green tea soup by montmorillonite

Considering that caffeine may lead to related diseases,the adsorption of caffeine in green tea soup was carried out by physical adsorption.Three kinds of adsorbents,activated carbon,montmorillonite and quartz sand,were chosen to adsorb caffeine from green tea soup in this experiment. The best adsorbent was montmorillonite,and the optimum adsorption conditions were obtained by response surface optimization:the adsorption time was 1.6 h,the tea soup pH was near 2.07,the montmorillonite dosage was 4%,and the final system caffeine content was 0.991%. After the adsorption,the loss of bioactive substances was not more than 6%. The results showed that montmorillonite was a feasible and practical method to remove the caffeine adsorbent in green tea,which provided the theoretical basis for the low-caffeine green instant tea.