Optimizing Wine Production from Hybrid Cultivars: Impact of Grape Maceration Time on the Content of Bioactive Compounds

Wine is a rich source of biologically active compounds, particularly polyphenols, which exhibit antioxidant and antiradical properties. The objective of this study was to optimize the vinification procedures of Polish wines from the hybrid white grape cv. 'Johanniter' and red grape cv. 'Regent', grown in the temperate climate of central Europe, by applying different skin maceration times: 4, 8, 12, 16, and 20 days. The wines were compared for their basic oenological characteristics and polyphenolic (UHPLC-MS) content as well as their antioxidant (FRAP test) and antiradical (DPPH test, ORAC-fl and EPR spectroscopy) capacities. Both wines demonstrated a substantial increase in their total phenolic content and antioxidant and antiradical capacities after a 4-day maceration; further treatment did not lead to considerable enrichment in bioactive compounds. Scavenging activities against nitroxyl radicals and DPPH were divergent for the tested wines and depended on the analytical method applied, which indicated distinct molecular mechanisms. In turn, the activity of peroxyl radical scavengers, antioxidant capacity, and the total content of phenolics were higher in all the red wine samples. The antioxidant and antiradical properties of the examined wines were comparable or even exceeded those determined for most wines produced in regions with a rich winemaking tradition.