Flavonoid Compositional Differences of Grapes Among Site Test Plantings of Cabernet franc

¹ Institut Supérieur de la Vigne et du Vin, INRA-IPV, Unité de Recherches Polymères et Techniques Physico-chimiques, 2, place Viala, 34060 Montpellier cedex, France
² Unité de Recherches sur la Vigne et le Vin, INRA, BP 57, 42 Rue Georges Morel, 49071 Beaucouzé cedex, France.

cheynier{at}ensam.inra.fr

Anthocyanin, flavonol, and tannin compositions of Cabernet franc grapes harvested from various places in the Loire Valley (France) in 1995 and 1996 were analyzed using HPLC methods. All data were treated by descriptive statistical method and principal component analysis (PCA) and related to previously established vineyard characteristics. Sites usually yielding intense and balanced Cabernet franc wines produced grapes with higher anthocyanin contents and anthocyanin to tannin ratios. Among tannin constituents, tannins from skins, prodelphinidins, and galloylated units were particularly abundant in grapes from lower potential vineyards. Although the anthocyanin content and qualitative distribution of tannins were also affected by vintage, differences in flavonoid composition among the sites were consistent between the two vintages studied. The effects of both growing site and vintage may be interpreted in terms of vine earliness.

Key words: grapes, flavonoids, anthocyanins, tannins, flavonals, growing site

Submitted on March 23, 1998
Revised on July 7, 1999