evaluation of changes in colour properties of clarified red and rosé wines

Effects of some selected clarifying agents on the colour of red and rosé wines were investigated. Selected clarifying agents were added in various doses to young red and rosé wines. Total monomeric anthocyanins and total polyphenols were estimated in all treated wine samples, as well as the colour intensity, hues and parameters CIE L*a*b*. In accordance with our expectations, contents of anthocyanins were decreased in all samples treated with clarifying agents. The most marked loss of total monomeric anthocyanins was observed after the application of bentonite. As compared with red wine samples, the percentage losses in luminance values (i.e. in colour intensity) of rosé wines were higher and the resulting values were significantly dependent on the variety. In red wines, the content of polyphenols was very markedly decreased after the application of the highest dose of casein while in rosé wine samples the most marked decrease in the content of polyphenols was observed after the application of the preparation polyvinylpolypyrrolidon.