Supercritical fluid impregnation of carotenoids from tucumã-do-Amazonas peel oil into corn starch

Tucumã-do-Amazonas (Astrocaryum aculeatum) is widely consumed in the Brazilian Amazon, generating residues such as kernels and peels that are rich in carotenoids, unsaturated fatty acids, and tocopherols. Oil from tucumã-do-Amazonas peel (TAP) can be recovered by supercritical fluid extraction (SFE) using CO₂, a clean technology. This oil can then be applied in supercritical fluid impregnation (SFI), also with CO₂, to produce a solid matrix with bioactive properties. This study aimed to produce carotenoid-rich corn starch particles using TAP oil by SFI. TAP oil was obtained by SFE at 35 MPa and 40 °C. Corn starch was used as the solid matrix, with approximately 0.25 g of oil and 0.25 g of starch placed in a stainless steel cell. The system was pressurized with CO₂ and subjected to different pressure (15, 25, and 35 MPa) and temperature (40, 50, and 60 °C) conditions. SFI yield, carotenoid-impregnated, and carotenoid loading in starch were evaluated. The highest impregnation yield (43.01%) occurred at 35 MPa and 50 °C, although it did not differ significantly (p ≤ 0.05) from 35 MPa/40 °C, 25 MPa/40 °C, and 25 MPa/50 °C. For carotenoids, optimal conditions were 35 MPa and 40 °C, achieving 90.84% impregnation and a loading of 1.6 mg β-carotene equivalen/g of starch. Increased pressure enhanced CO₂ density and solvating power, improving interaction with the oil and promoting its deposition into the starch matrix. Further studies are needed to assess structural changes in starch particles and product stability. Overall, SFI proved effective for producing carotenoid-enriched corn starch, demonstrating the potential of agroindustrial residues like TAP oil as sources of bioactive compounds.