Effect of Processing on the Phenolics and Color of Cabernet Sauvignon, Chambourcin, and Noble Wines and Juices

A study was conducted to determine the effect of processing method on the phenol composition and color of wines and juices from Cabernet Sauvignon (Vitis vinifera), Chambourcin (French-American hybrid), and Noble (Vitis rotundifolia). Processing treatments included immediate press for wine and juice, hot press for wine and juice, and skin fermentations (3, 7, 14 days for Noble; 7, 13, 21 days for Cabernet and Chambourcin) for wines. Phenols tentatively identified and quantified by HPLC included: coutaric acid, caftaric acid, gallic acid, ellagic acid, catechin, epicatechin, and procyanidins B3 and B4. Immediate press wines and juices had the lowest levels of all phenols measured, while skin fermentation wines had higher levels of nearly all phenols than hot press wines or juices. However, hot press Chambourcin wines and juices had higher total phenols than skin fermented wines. Levels of gallic acid, epicatechin and procyanidins B3 and B4 generally increased with longer skin fermentation times. Caftaric acid, coutaric acid, ellagic acid (Noble only), and catechin did not show consistent trends between treatments. Skin-fermented Noble wines had very high levels of gallic acid and epicatechin, and contained ellagic acid. However, caftaric acid and procyanidin levels were very low in all Noble wines. Cabernet had high levels of catechin and procyanidins, and Chambourcin had the lowest levels of catechin and epicatechin. Noble had the lowest degree of anthocyanin polymerization. Skin fermented Noble wines had greater color intensity than hot press wine or juice, but hot press Chambourcin wine and juice had greater color intensity than skin fermented wines. Cabernet hot press wine and juice had similar color as skin fermented wines.