tailieunhanh - Đề tài: STUDY ON THE EXTRACTION AND ISOLATION OF CAFFEINE FROM GREEN TEA Camellia sinensis (L.)

Caffeine is one of the most popular compounds which are taken everyday by millions of people all around the world. Due to its pleasant flavor and stimulating effect, caffeine is more common than any chemicals and has been consumed for hundreds of years. It is also a key component of many popular drinks and food, such as tea, coffee, soft drinks, energy drinks and chocolate. Recently, caffeine has been used as a drug. It can stimulate the central nervous system and make people more alert, less drowsy and improve coordination. With its unique properties, caffeine has been combined with certain pain relievers or medicines for treating headaches. | After extraction step, caffeine adsorption and desorption with various adsorbent columns were studied. The tea extracts from the optimal extraction condition were passed through different adsorbent columns of XAD-4, XAD-7, IR-120H and activated carbon with a flow rate of 1 ml/min. XAD-4 was found to have the highest adsorption affinity for caffeine and lowest one for EGCG while the contrary results were observed for IR-120H. It was found that the suitable amount of XAD-4 adsorbent for one-time adsorption of caffeine is 7g. Several solvents were used for one-time desorption of caffeine from the adsorbent columns with a flow rate of 1 ml/min and acetone was found to possess the highest strength for caffeine desorption. 125 ml of solvent was found as the suitable volume for one-time desorption of caffeine from the adsorbent columns. EGCG was not found in the desorption solutions from XAD-4, XAD-7 and activated carbon. However, EGCG was found in the desorption solutions by ethanol and acetone from IR-120H column.