Co-Product of Pracaxi Seeds: Quantification of Epicatechin by HPLC-DAD and Microencapsulation of the Extract by Spray Drying

Abstract

In the industrial processing of fruits, co-products are generated, which are often not used. The pracaxi co-product, obtained by cold pressing its seeds, contains phenolic compounds with antioxidant activity, which in this work were extracted and microencapsulated by spray drying. The pracaxi extract was characterized by Fourier-transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC-DAD), and its antioxidant activity was quantified by the ABTS and DPPH assays. Total polyphenol and flavonoid contents in the extract and microparticles were determined by UV-Vis spectrophotometry. Microparticles were then characterized regarding their moisture content, morphology (by scanning electron microscopy), size, polydispersity index and zeta potential. The FTIR spectra revealed functional groups that may be related to phenolic compounds. The extract showed good antioxidant activity according to both selected assays, while the HPLC-DAD analysis evidenced epicatechin as the main compound, whose content was quantified and validated according to the guidelines of recognized national and international agencies. The total polyphenol contents were 20.61 ± 0.20 mg gallic acid equivalent (GAE)/g in the extract and 18.48 ± 0.10 mg GAE/g in the microparticles, while the total flavonoid contents were 28.29 ± 0.70 mg quercetin equivalent (QE)/g and 13.73 ± 0.10 mg QE/g, respectively. Microparticles had a low moisture content, spherical shape, size less than 1 μm and negative zeta potential. Furthermore, they were able to satisfactorily retain phenolic compounds, although in a smaller amount compared to the extract due to small losses resulting from degradation during the drying process. These results, taken as a whole, demonstrate that the pracaxi co-product can be a promising candidate in obtaining products of interest for the cosmetic and food sectors by aiming to exploit its antioxidant activity.