Major Phenolic Compounds in Ripening White Grapes

¹ Department of Food Science and Technology, NYSAES, Cornell University, Geneva, NY 14456.

The concentrations of hydroxycinnamic acid tartrates, flavan-3-ols, and oligomeric procyanidins in ripening white grape cultivars grown in New York were analyzed during the 1986 and 1987 seasons. During maturation of grape berries, hydroxycinnamic tartrates decreased continuously to a low concentration at harvest, while flavan-3-ols, procyanidins, and their gallates increased sharply at veraison and then decreased to their lowest concentrations at harvest. Significant seasonal and cultivar variations in the amounts of phenolic compounds during ripening were noticed. A larger quantity of hydroxycinnamic tartrates was found in berry skin than in the flesh, while larger quantities of flavan-3-ols and procyanidins were observed in the berry flesh. These findings partially explain the differences in browning potential of grapes in relation to cultivar and seasonal variations, free-run juice, and hard-pressed juice.

Key words: phenolics, procyanidins, flavan-3-ols, maturation, white grapes

Submitted on April 8, 1988