Wine Chemical Composition and Radical Scavenging Activity of Some Cabernet Franc Clones

Abstract

BACKGROUND: Three clones of Cabernet Franc (Nos. 02, 010 and 012) were selected in the last phase of clonal selection in Serbia. Wines made from each clone were assessed for quality parameters and taste during five consecutive vintages (2008-2012) and compared to the standard. The wine quality was determined based on the following parameters: alcohol, total extract, anthocyanins, tannins, pH, titratable acidity, volatile acidity, aldehydes, esters and reducing sugars, relative density, ash, colour, tonality, and tasting score. In the last year of the study, grapes and wines of Cabernet Franc clones and a standard were subjected to a chemical analysis of their phenolic composition, resveratrol and radical scavenging activity. In the last year of the study, grapes and wines of Cabernet Franc clones and a standard were subjected to a chemical analysis of their phenolic composition, resveratrol and radical scavenging activity. Methods: Chemical analyses of grapes and wines along with sensory and radical scavenging activity evaluations were done according to the standard procedures. Results: The wines of the clone No. 010 showed some superior properties compared to the other two clones and the standard; in five-year period the average concentration of anthocyanins (179 +/- 3.8 mg/L) and polyphenolics (1.85 +/- 0.02 g/L) was significantly higher than in wines of clones and the standard, (168-173 mg/L and 1.63-1.74 g/L for anthocyanins and phenolics, respectively). Furthermore, the same clone had a higher alcohol content (13.97 +/- 0.03%) in each year of the study, which indicated that it ripened faster than other clones (13.06-13.08 %) and compared to the standard (13.04 +/- 0.07%). This finding suggested that the clone No. 010 could possibly have a significant economic impact and further increase popularity of Cabernet Franc in a cooler climate viticultural region. It was also found to have the highest contents of aldehydes (488 +/- 1.54 mg/L) and esters (322 +/- 0.71 mg/L) compared to aldehydes (452-467 mg/L) and esters (290-310 mg/L) measured in other wines. Finally, the highest amount of phenolic compounds (1220 +/- 40 mg/kg) and resveratrol (70 +/- 3.3 mg/kg) were found in the grapes of the clone No. 010. The present study revealed a strong correlation of total phenolic contents and anthocyanins with radical scavenging activities (0.936 and 0.929, P lt 0.001, respectively) indicating that this activity of wines was derived mainly from their phenolic compounds. Conclusion: The wine of the clone No. 010 contained the highest concentration of aldehydes, esters, anthocyanins, polyphenolics and resveratrol and consequently achieved the best tasting score. This clone may offer a new Cabernet Franc wine with geographical indication.