Effect of Chitosan and 5-Chlorosalicylic Acid on Total Phenolic Content of Grapes and Wine

Cabernet Sauvignon vines were treated with chitosan and 5-chlorosalicylic acid, applied separately and in combination at three weekly intervals from fruit set to harvest. None of the treatments, either alone or in combination, had any significant effect on total phenolic content of the grapes compared to control. However, 5-chlorosalicylic acid treatment, either alone or in combination with chitosan, caused 15% and 12% reductions, respectively, in extraction of total phenolics into the wine during vinification and a decrease in wine quality index. The finding of reduced wine quality may be important should elicitor-based protectants be integrated into disease-management programs.