Optimization of Solid Lipid Nanoparticles for the Encapsulation of Carotenoids from Cucurbita moschata Pulp

The encapsulation within nanostructures of lipophilic bioactive molecules, such as carotenoids, can be a solution to improve their bioaccessibility in foods and beverages. Among vegetables/fruits rich in carotenoids, pumpkin can be considered a functional food with interesting healthy effects. The aim of this work was to optimize the production of Solid Lipid Nanoparticles (SLN) for the encapsulation of carotenoid-rich extracts obtained from pumpkin (Cucurbita moschata) pulp by ultrasound-assisted extraction (UAE) at 45°C for 30 min, using hexane:isopropanol (60:40, v/v). The extracts were characterized by in vitro spectrophotometric assays and chromatographic analysis. Hot high-pressure homogenization (HPH) was the method of choice for SLN production because it is easily scalable and it does not involve the use of organic solvents. To optimize the encapsulation conditions, β-carotene was used as model molecule. This choice was supported by the chemical-analytical characterization, which identified β-carotene as the main carotenoid of the pumpkin extracts. SLN loaded with 1% β-carotene have dimensions (~350 nm) compatible with increased intestinal absorption. Furthermore, ABTS assay showed that the technological process did not change the antioxidant capacity of β-carotene.