Extração de folhas de Moringa oleifera utilizando CO2 supercrítico + co-solvente etanol

Abstract

Moringa oleifera leaf extracts were obtained by supercritical extraction with CO2 using ethanol as cosolvent (scCO2 + EtOH). The experimental conditions were investigated varying temperature (35 – 80 oC), pressure (150 – 25 MPa), and mass ratio between ethanol and raw material. The phenolic acids (gallic, vanillic, and p-coumaric acids) and flavonoids (catechin) were identified in all extracts, except for the extract obtained without the co-solvent ethanol. The main compounds by GC–MS were 1-triacontanol, nonacosane, heptacosane, phytol, γ-tocopherol, and α-tocopherol. Extracts obtained at 35 oC showed higher concentrations of total phenolic compounds, and higher antioxidant capacity measured by the DPPH, and FRAP methods, however, the lowest extraction yield. The central point scCO2 + EtOH extraction conditions (60 oC and 20 MPa) had the best-combined results for yield (4.4%), total phenolic compounds (24 ± 1 mg GAE g -1), DPPH (77 ± 2 μmol Trolox g-1), FRAP (265 ± 9 μmol Trolox g-1) and the presence of bioactive compounds. Supercritical fluid extraction with CO2 is a clean technology that employs low temperatures, producing high-quality extracts. Moringa oleifera leaf extracts showed different compositions according to the experimental conditions evaluated. The use of ethanol as a cosolvent and high temperatures positively influenced the extraction yield. All extracts showed antioxidant potential. Catechin, gallic, vanillic, and p-coumaric acids were the main phenolic compounds identified. The extract obtained at the central point condition showed higher antioxidant potential, yield, and concentration of bioactive compounds.