Multivariate analysis caffeine extraction from roasted and ground coffee powder using eutetic mixtures as a sustainable system

Coffee, a raw material rich in bioactive molecules, has a long history of consumption in Brazil and worldwide. Among these molecules, caffeine (1,3,7-trimethylxanthine) stands out for its stimulating, anti-inflammatory, and diuretic properties. With growing environmental concerns, programs have emerged to encourage the use of less environmentally aggressive processes. Over the past 10 years, Deep Eutectic Solvents (DES) and their natural precursors counterpart (NADES) have gained prominence. These solvents are biodegradable, biocompatible, have reduced flammability, high dissolution capacity and are cost-effective. This study aims to evaluate the effect of the variables (factors) such as time, temperature, volume of water and mass of NADES (choline chloride:lactic acid) on the extraction of caffeine from roasted and ground coffee powder using NADES as an extracting solvent, using the water bath method employing factorial design with central point. Twenty experiments were carried out, and the best experimental condition in which the greatest caffeine extraction was obtained was when the experiment used a time of 15 minutes, temperature of 90 °C, volume of water 5 mL and mass of NADES 10 g, obtaining 56.1 mg/g of caffeine, in accordance with the experimental parameters of the factors in the factorial design used. Through multivariate analysis, it was found that the variables: NADES amount and temperature, had the greatest influence on the extraction process. In addition, through ATR-FT-IR it was possible to identify the bonds and interactions between the constituents of the studied NADES.