Extração e caracterização de compostos do resíduo casca de café

Abstract

Brazil is the largest coffee producer and exporter in the world, but this great production also generates enormous volumes of waste materials during the process of separating the commercial product. The amount of coffee husk produced during the processing of the coffee beans represents 50% of the production. Looking at this problem, the aim of this study was to obtain extracts of coffee husks using different solvents, evaluate their composition in terms of caffeine, and evaluate the antimicrobial activity of the extracts obtained. For the extractions made by Soxhlet, using solvents of different polarities and selectivities, it can be observed from GC-MS, FTIR results that the extracts obtained in different solvents differ in the chemical composition, and that chloroform and dichloromethane were the only ones that extracted the caffeine, being the most efficient chloroform extract. The hydrophilic extracts were obtained using different rations between ethanol and water, and extractions at room temperature and at 40 °C. Changings in the solvent proportions did not change the chemical profile of the extracts obtained, however changed the amount of caffeine extracted. Caffeine was the major compound extracted and the best condition for its extraction was at room temperature with 40% of ethanol solution. Antimicrobial activity of the lipophilic extracts was evaluated by disk diffusion method and the extract obtained with 40% ethanol the activity was evaluated using the minimum inhibitory concentration method. None of the extracts showed antimicrobial activity against the bacteria tested. It can be concluded in this work that the coffee rusks shows considerable amount of caffeine and could be used to the extraction of this compound, contributing to the transformation of this vegetable waste into a value added product and could help to reduce the environmental impact generated by the disposal of this toxic residue. . Thus, it can be concluded that coffee husks have great potential for caffeine extraction, adding value to this vegetable waste and contributing to the recovery of waste produced in the coffee processing which would decrease the environmental impact generated by the disposal thereof.