Resumo:
In this work, the effect of the water-coffee ratio, time, and stirring speed, on the total soluble solids, extraction rate, titratable acidity, and extraction yield was evaluated for the percolation of coffee in a horizontal ribbon blender equipment. The coffee extract was obtained in a pilot unit at a constant temperature of 85°C and varying the water-coffee ratio from 4:1 to 10:1; the stirring speed between 30 and 95 RPM and the extraction time from 10 to 60 minutes. It was determined that the water-coffee ratio was the factor that had a significant influence on all the response variables, while time and stirring were significant for the extraction rate and titratable acidity. The optimal setup among the studied conditions was using a water temperature of 85°C, a water-coffee ratio of 4:1, and a stirring speed of 66 RPM for ten minutes. At these conditions, an extract of 5.85% TDS, 14.54% as yield, an extraction rate of 654.8 g/h, and a content of 5.62 mg of CGA/mL was obtained. Hence, this study presents an alternative process to obtain coffee extract in producing soluble coffee at a low industrial scale.
