Phenolic Compounds from the Fermentation of Cultivars Cabernet Sauvignon and Merlot from the Slovenian Coastal Region

Phenolic Compounds from the Fermentation of Cultivars Cabernet Sauvignon and Merlot from the Slovenian Coastal Region

Iztok Klenar¹*, Marin Berovič² and Mojmir Wondra³¹Vinakoper, Šmarska 1, SI-5000 Koper, Slovenia
²Faculty for Chemistry and Chemical Technology Department of Chemical, Biochemical and Ecological Engineering, University of Ljubljana, Askerčeva 5, SI-1115 Ljubljana, Slovenia
³Department of Food Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia

Article history:
Received: December 17, 2003
Accepted: February 16, 2004

Key words:
fermentation, phenols, anthocyanins, tone and colour intensity

Summary:
Large scale fermentation of the cultivars Cabernet Sauvignon and Merlot from the Slovenian coastal region was performed in Bücher-Vaslin roto tank vinificators. Six different areas, Prade, Kortina, Škocijan, Ankaran, Labor and Hrvatini, were selected for this study to investigate total phenols, anthocyanins, tannins and colour density, as well as pH, titratable acidity, sugar content and ethanol. Anthocyanins and phenolic compounds were found to be in generally higher concentrations (up to 4240 mg/L) in Cabernet Sauvignon. Prolongation of the fermentation phase with Merlot gave even reduced concentrations of anthocyanins, a phenomenon which was not observed in Cabernet Sauvignon. The highest concentration of anthocyanins was found in Merlot from the Kortina location (735 mg/L), and in Cabernet Sauvignon from the Labor location (998 mg/L). The highest concentration of tannins (1828 mg/L) was found in the grapes of Cabernet Sauvignon from the Ankaran location, while in Merlot 1280 mg/L was detected in a sample from the Prade area. The tone of colour and its intensity reached full maturity in Cabernet Sauvignon. Merlot from the Kortina location reached the highest colour density of 1.57, while in a sample of Cabernet Sauvignon from Hrvatini colour density was 2.89. Only small differences were detected in colour quality between Merlot and Cabernet Sauvignon.

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