Avaliação da extração de compostos bioativos presentes na erva mate (Ilex paraguariensis) utilizando o líquido iônico 2-hidroxietanolamina (2-HEAA)

Abstract

Yerba mate has a high concentration of phenolic compounds that act as antioxidants and help in the prevention of various diseases, such as cancer. The use of ionic liquids in the process of extraction of bioactive compounds has been increasing because it is a solvent based on the principles of green chemistry. In this work was evaluated the extraction of phenolic compounds, antioxidant activity and flavonoids present in yerba mate using as solvent the ionic liquid 2- hydroxyethanolamine acetate (2-HEAA). The yerba mate obtained in the city of Laranjeiras do Sul - PR were sanitized, dried in the oven, ground and separated into different granulometry. A preliminary test was performed to verify the concentration of matte weed particle per solvent that would extract higher polyphenol contents. A central rotational composite design (DCCR) was performed to evaluate the influence of temperature, particle size, solvent concentration and agitation speed on the extraction of phenolic compounds using the ionic liquid 2-HEAA. The kinetic study was performed using the best operational conditions obtained by the experimental design and it was identified the best time for the extraction to come into equilibrium. The determination of phenolic compounds were based on the method using the Folin-Ciocalteau reagent and the samples absorbance reading were performed on a spectrophotometer at 765 nm. The method used to antioxidant activity analysis was based on ABTS radical inhibition, analyzing the decrease in absorbance in spectrophotometer at 734 nm. Flavonoids were determined by the method based on the extract reaction with AlCl3, NaNO2 and NaOH and absorbance reading on spectrophotometer at 510 nm. The results obtained in the preliminary test showed that 2 grams of yerba mate particles per 20 grams of solvent was the test that best extracted compounds of yerba mate. In the experimental design the optimum parameters for phenolic and antioxidant compounds were similar. The optimum parameters for flavonoids extraction that showed differences with phenolic compounds and antioxidant activity were temperature and solvent concentration. In general, the optimum parameters for extraction of the three components were 60oC, 100 Mesh, 75% solvent concentration and 180 rpm. The kinetic study showed that the extraction of phenolic compounds, flavonoids and antioxidant compounds present in yerba mate using the 2-HEAA solvent is fast and that the equilibrium time was approximately 200 minutes. The kinetic model evaluated was the first-order nonlinear equation, which fitted the experimental data with coefficients of determination between 0.94 and 0.99.