Café: um produto modelo para o ensino de Química em uma perspectiva sustentável

Abstract

Coffee, historically known and consumed in Brazil and in the world, is a raw material rich on bioactive molecules, among them, caffeine, for its organoleptic, stimulant, antiinflammatory and diuretic characteristics. Thus, the main objective of this work was the extraction of caffeine from roasted and ground coffee powder for the construction of a contextualized and interdisciplinary teaching proposal, based on the 12 Principles of Green Chemistry, articulating popular and scientific knowledge to provide a teachinglearning process significant. In addition, the present work aims to study and perform environmentally friendly extractions, using eutectic solvents to obtain bioactive substances (e.g. caffeine), as well as to quantify the caffeine extracted by the standard addition method and to identify, through a statistical tool, which variables exerted significant influence on extraction. The plant extracts were obtained by water bath, using NADES (Choline chloride:lactic acid) and water. These extracts underwent quantitative tests in the spectrophotometer, using the standard addition method and were compared to identify better results using a statistical tool (Chemometrics). The analyses in the spectrophotometer revealed the presence of caffeine and chlorogenic acid in the extracts. The data obtained served to compose the Didactic Sequence proposal for the Environmental Chemistry discipline, which was evaluated, through a semi-structured questionnaire, by the teacher who the discipline at the Teacher Training Center, at the Federal University of Recôncavo from the Bahia.