KINETIC EVALUATION OF THE PRESSURIZED LIQUID EXTRACTION FROM TUCUMÃ-DO-AMAZONAS PEEL

Tucumã-do-Amazonas (Astrocaryum aculeatum) is a very popular fruit in the Amazon region. The most consumed part of this fruit is the pulp, which can be eaten raw or used as a filling for sandwiches, tapiocas, and other dishes. The large consumption of fruit pulp generates waste such as peels and seeds, which can be sources of bioactive compounds such as fatty acids, carotenoids, phenolic compounds, and tocopherols. The recovery of agro-industrial waste to obtain compounds can be achieved by various extraction methods, including more sustainable extraction methods based on the use of green solvents. Among these techniques, pressurized liquid extraction (PLE) stands out, applying high-pressure solvents to keep the solvents in a liquid state even above their boiling point. The objective of this work was to obtain extracts from defatted tucumã-do-Amazonas peels (DTP) using PLE. The peels were previously defatted by supercritical CO₂ extraction at 35 MPa and 40 °C and then subjected to PLE, where a kinetic study was performed, with extracts collected along time. The solvent used was a mixture of ethanol and water (75% EtOH) and the temperature evaluated was 100 °C. Kinetic curves were plotted, representing the accumulated global yield (X₀) and total reducing capacity (TRC) as a function of time, to evaluate the mass transfer mechanisms of the process, and the three-line Spline kinetic model was applied to model the curves and evaluate the periods of constant extraction rate (CER), falling extraction rate (FER), and diffusion-controlled (DC). X₀ at the end of the PLE was 24.77 g ext/100 g DTP. According to the kinetic modeling based on the Spline model, in the CER stage, in a time of 11 min, 11.91 g ext/100 g DTP was extracted, with the FER stage then reaching a yield of 21.72 g ext/100 DTP, with a time of 48 min, which represents a recovery of almost 80% from the DTP. For TRC, a time of 70 min is necessary to obtain an extract with 43.60 mg GAE/g DTP. Thus, PLE is a promising technique that can be used to valorize DTP, producing an extract with high total reducing capacity.