Extraction and chemical characterization of polyphenolic compounds from blackcurrant (Ribes nigrum L.) pomace

Berry pomace is the solid residue of berries after they have been processed for juice and wine making or to obtain other liquid extracts. It primarily consists of skins, seeds, and pulp left behind after berry processing. Rich in fiber, antioxidants, and other bioactive compounds, especially polyphenols, berry pomace holds significant potential for various applications. The objective of this study was to determine optimal conditions for extracting bioactive ingredients from blackcurrant ( Ribes nigrum L.) pomace and to identify the chemical compounds present in the extracts. Comprehensive high-resolution mass spectrometry (HRMS)-based chemical fingerprinting was applied to analyze the chemical profiles of different R. nigrum pomace extracts with a special emphasis on polyphenols. Among the solvents tested, 50% aqueous ethanol proved to be the most effective extraction solvent, yielding the highest total phenolic content (approx. 2000 mg GAE/100 g pomace dry mass). Using a flow injection HRMS analysis, a total of 110 different polyphenols and other extractives were identified, representing 21 distinct compound classes. The most prevalent class was flavonoids, comprising different phenol glucosides and rutinosides. These compounds hold significant potential for use in nutrition, cosmetics, pharmaceuticals, and agriculture, providing natural antioxidant or antimicrobial properties, as well as potential benefits for human gut health and blood sugar regulation.