Ethanolic and hydroalcoholic extracts of pitanga leaves (Eugenia uniflora L.) and their fractionation by supercritical technology

Abstract

Hydroalcoholic extracts prepared by conventional methods (in stirred vessel at 25 °C and 1 bar) and, hydroalcoholic and supercritical carbon dioxide (scCO2) extracts prepared in fixed bed extractors (60 ºC and 400 bar) were obtained from pitanga leaves (Eugenia uniflora L.) in order to recover phenolic compounds. Hydroalcoholic and ethanolic extracts obtained in fixed bed were further fractionated in four separators by gradual pressure reduction, using scCO2 as an antisolvent. All extracts and fractions were characterized in terms of extraction yield and the presence of total phenolics and flavonoids. Solvents were found to significantly influence the extraction yields and composition. Yields increased as a function of polarity, whereas the hydroalcoholic extractions displayed the highest yields and the highest amounts of extracted phenols and flavonoids.