Phenolic composition and antioxidant activity of red, rosé and white wines originating from Romanian grape cultivars

The objective of this work was to study the phenolic profile and composition in relation to antioxidant activity of fifteen samples of commercial red, rose and white wines originating from six native grape varieties and produced in important wine regions from Romania. The profile and quantification of major phenolic compounds were performed by direct injection of wines in the LC-MS system, using DAD and ESI (+) MS techniques, in parallel with the total phenolic content (TPC) measured by spectrometry and the free radical scavenging activity, against 2,2-diphenyl-1-picrylhydrazyl (DPPH). There were identified 38 polyphenols in wines, including 3 flavan-3-ols, 17 flavonols, 12 anthocyanins and 6 stilbenes. The red wines had significant higher phenolic content and antioxidant capacity, followed by rose and white wines. The richest phenolic content and antioxidant activity was obtained for ‘Feteasca Neagra’ (Tohani) among red wines and for ‘Feteasca Regala’ (Jidvei) among white wines. TPC values were positively correlated with the antioxidant capacity in all white wines and only for the red ‘Feteasca Neagra’ assortment, while for the ‘Babeasca Neagra’ assortment negative correlations were obtained. From the 38 variables, flavan-3-ols have exerted the greatest influence on wine differentiation, based on their colour (red, rose and white). The study also revealed significant differences between cultivars, both qualitative and quantitative, in terms of their polyphenolic composition, that could be important in the cultivar authentication of wines from these varieties.