Supercritical extraction from red propolis and fractionation of its hydroalcoholic and ethanolic extracts using CO2 as anti-solvent / Extração supercrítica da própolis vermelha e fracionamento de seus extratos hidroalcoólicos e etanolicos usando CO2 como anti-solvente

Technologies for extraction and fractionation of phenolic compounds from a typical propolis from northeastern Brazil, called red propolis, using supercritical fluids may represent an environmentally correct alternative to the current extraction processes, as they are included in the concept of "green chemistry". The objective of this work was to extract and fractionate the phenolic compounds from red propolis: I) Using supercritical carbon dioxide (scCO2) as solvent and ethanol as co-solvent to obtain an ethanolic extract; II) Using scCO2 as solvent and a mixture of ethanol: water (70:30, v / v) as co-solvent to obtain a hydroalcoholic extract. After extraction, the ethanolic and hydroalcoholic extracts were fractionated using scCO2 as antisolvent at a constant temperature of 50 ºC, subjected to four gradual pressures, in a sequential of separators operated at 200, 100 and 80 bar, at the end, atmospheric pressure (1.013 bar). The procedure was characterized according to extraction yield; total phenols, total flavonoids, antioxidant activity and color. It was found that the pressure influenced the yield and the concentration of the phenolic compounds in the extracts, demonstrating that the most efficient fractionation process occurred in the first and second separators. Overall, all extracts showed high antioxidant activity.