OPTIMIZATION OF SUNFLOWER OIL EXTRACTION USING PRESSURIZED ETHANOL - PROCESS WITH INTERMITTENT PURGE OF SOLVENT

Extraction with pressurized ethanol has proven to be an efficient, green, and solvent-saving method. We sought to identify the significant process variables and, subsequently, the optimum point for extracting sunflower seed oil. The extraction using intermittent solvent purge occurred in Dionex 150 equipment. The variables were selected using a linear experimental design with the following independent variables: contact period between the matrix and solvent in each cycle (St), the temperature (T), and the volume of solvent (VS). The seeds used in this study contain approximately 55% oil. The best result (47% concerning the total mass of the seeds) was obtained under the conditions of 84 ºC (T) and 110% (VS), being quite considerable when compared to the total oil content of the seed. Since the static time was not significant, the optimum point was determined from the analysis of the influence of the T and VS parameters on the extraction yield using first and second-order models. It was concluded that, with R² = 0.99, the quadratic model used proved to be quite adjusted to the experimental and predictive data. There was no significant difference for VS (p≥0.05), suggesting the possibility of extraction in a short time and with low use of solvents.