Extraction and Crystallization of Caffeine from Coffee Husks (Coffea Arabica Var. Catuaí)

Brazil is the largest producer and exporter of Arabica coffee in the world. The increase in the residue generated after the processing of the grain is proportional to the increase in coffee production. The ratio between obtaining the processed bean and the coffee husk is generally around 1:1 (m/m), and a high volume of waste is generated during the processing. The present work aims to propose a technology for the use of this residue, carrying out crystallization of the caffeine extracted from the coffee husk of the Coffea arabica, Red Catua & iacute; type. To achieve the proposed objective, a central composite design was carried out for the roasting step to optimize the extraction of caffeine. The optimum temperature and time obtained within the analyzed range of these variables were 147.6 degrees C and 5.3 min, respectively, and indicated the maximum extraction of caffeine content of 43.08% in mass. The crystallization of caffeine from coffee husk was carried out in a supersaturated solution with seeds obtained by previous crystallization of caffeine. The experiments indicated crystalline growth of the added seeds, even in the presence of impurities and possible crystallization inhibitors. In this way, crystallization was decisive in the purification of the caffeine extracted from the coffee husks, reaching a purity of 88% for caffeine.