HPLC-DAD-ESI/MS MONITORING OF STILBENES CONTENT IN VRANAC RED WINES PRODUCED WITH TRADITIONAL AND MODERN FERMENTATION METHODS

Quantification of stilbenes was performed on Vranac wines (vintage 2008 and 2009) produced by traditional and modern fermentation methods, applying different enological additions (enzyme, oak chips and grape tannins). Stilbenes, trans-resveratrol and trans-resveratrol-3-glucoside were determined using the high-performance liquid chromatography (HPLC) coupled to a diode array detector (DAD) and electrospray mass spectrometer (ESI-MS) technique. Trans-resveratrol ranged from 0.09 to 3.30 mg/l and trans-resveratrol-3-glucoside from 1.13 to 2.60 mg/l. The vintage, fermentation tanks and enological additions influenced the content of stilbenes. Wines from vintage 2008 presented higher amount of stilbenes (on average: 1.89 mg/l) compared to the wines from 2009 (on average: 1.59 mg/l), probably because of the difference in the temperature and humidity in both years. Application of modern fermentation tanks (Sifa and Ganimede) followed by additions of enzyme, oak chips and grape tannins resulted in a higher amount of stilbenes. Principal Component Analysis (PCA) presented grouping of wines according to the applied fermentation method.