Background. The utilization of phenolic compounds is limited by many factors, such as low solubility, low permeability, lability, rapid release, vulnerability towards environmental impacts and low bioavailability. To overcome these constraints, polyphenols can be closed within lipid-based and protein-based nanoparticles. In this study, nanocapsules derived from egg powder,  enriched with chokeberry pomace extracts were examined. The content of antioxidant compounds (polyphenols, anthocyanins, phenylpropanoids, total phenolic compounds) and antioxidative  potential (with the participation of radicals: DPPH^•, ABTS^•+ and FRAP assays) were determined to assess the influence of the extraction method (heat extraction, ultrasound assisted extraction, stirring extraction) and encapsulation process of the fruit extract.
Results and conclusions. In the present study, the highest amounts of most examined compounds (regardless of the powder type) were achieved by heat extraction. The lowest values were obtained by stirring the solution at room temperature. The highest antioxidative potential towards radicals was assessed when ultrasounds were used as the extraction factor. Furthermore, the  closure of fruit extracts in the protein shell appears to act in a protective manner on the antioxidant compounds present in the extract. The results show that the extraction method applied in the  phase of preparing samples to the analysis is of great importance for determining the antioxidant compound content and antioxidant capacity.