Anthocyanins, Phenolics, and Color of Cabernet Franc, Merlot, and Pinot Noir Wines from British Columbia

Abstract

Changes in phenolics (anthocyanins, flavonols, tartaric esters, and total phenolics) during ripening of grapes and in phenolics and color during vinification and aging of Cabernet Franc, Merlot, and Pinot Noir wines were studied. Anthocyanins in grape skins showed variations in accumulation pattern, concentration, and distribution depending on variety and to a lesser extent on season. During vinification, colorless phenolics increased during alcoholic fermentation, reached maximum values at pressing, and remained stable during malolactic fermentation and subsequent storage. Anthocyanins and color density, on the other hand, increased during the early stages of alcoholic fermentation, reached maximum values 2−3 days after the start of fermentation, decreased during malolactic fermentation, and slowly declined during subsequent storage. Viticultural practices that increased cluster sun exposure generally led to higher phenolics and color density of wines, whereas changing yeasts used for fermentation had minimal effects. Keywords: Wine color; polyphenols; flavonoids; flavonols; anthocyanins; tartaric esters; grapes; polymeric pigments; HPLC analysis; yeast