Fracionamento de extratos de subprodutos industriais de maracujá-azedo (Passiflora edulis Sims.) utilizando CO2 supercrítico e líquidos pressurizados

Abstract

Bioactive compounds extracted from natural sources are widely studied because of their biological and industrial application attractiveness. Previous studies demonstrated that passion fruit (Passiflora edulis Sims.) by-products are rich sources in bioactive compounds of different classes. However, sustainable fractionation processes aiming to concentrate such extracts are poorly explored in literature. This work aimed to evaluate the fractionation of seeds and pulp residues from passion fruit. In the first step, a supercritical fractionation unit with two on-line separators (S1 and S2) was assembled. The static and dynamic solubilities of the lipid extract in supercritical CO2 (SC-CO2) were measured. The fractionation integrated to extraction using SC-CO2 (35 MPa, 40 ºC) was performed in the temperature range of 50-80 ºC and the pressure range of 17-25 MPa in S1 and 9 MPa in S2, with further analysis of tocols, squalene and carotenoids content in the fractions precipitated in both separators (F1 and F2) and depressurization (F3). The economic analysis of the process was performed using the software SuperPro Designer 9.0 ® . Finally, in the last step of this work, Hansen solubility parameters (HSPs) were used to select the solvents for pressurized liquid extraction (PLE) of passion fruit by-products, in order to concentrate piceatannol in the polar extracts. The enzymatic inhibition potential of two enzymes associated with neurodegenerative effects of such extracts was also investigated. The solubility presented the crossover phenomenon at temperatures above 50 ºC in the evaluated pressure range. Supercritical fractionation concentrated squalene in F3 about 5.2 times (4,790.5 mg/kg of extract) compared to the non-fractionated extract. The isomers δand β/γ-tocotrienol were concentrated in F2. The process showed economic viability for this fraction production at pilot scale, with a cost of US$ 277-384/kg of extract. For PLE, the selected solvents were: benzyl alcohol, ethyl acetate, and ethanol. The HSPs calculation demonstrated that the relative energy distance (Ra) between the solvent and the piceatannol was smaller for benzyl alcohol. Nonetheless, the most concentrated extract in piceatannol was obtained using ethanol in multi-cycle extraction at 110 ºC. Such result could be explained by the process' dependence on kinetic parameters over the thermodynamics parameters. Regarding enzymatic inhibition, the most concentrated extract in piceatannol achieved better inhibition potential for acetylcholinesterase (IC50 = 29.420 ± 1.615 μg/mL) and lipoxygenase (IC50 = 27.682 ± 2.477 μg/mL). Overall, this work confirms that high pressure fractionation processes are sustainable alternatives to the enrichment of extracts from passion fruit by-products, especially regarding δand β/γ-tocotrienol, squalene and piceatannol content. The bioactivity of the piceatannol enriched extract was evidenced as antineurodegenerative effects, reinforcing the necessity of more application studies of the extracts in natural medicine.