Composition of Arkansas Grapes During Maturation

Changes in organic acid and glucose content during maturation and ripening of grapes grown in Arkansas in 1973 are shown for four French hybrid varieties, S5279, S10878, SV23- 657, and S13053, and for four rotundifolia varieties, Scuppernong, Tarheel, Fry, and Magoon. In all varieties the concentrations of malates and tartrates were highest in the early stages of berry growth after veraison. During ripening the titratable acidity decreased and Balling and pH measurements increased. Although varieties reached maturity on different dates, changes in parameters followed similar curves typical for grapes of the species but occurring over a short period (Johnson and Nagel 1976, Winkler 1970). Rotundifolia varieties showed unacceptable Balling-acid ratios as well as irregular maturation progress in the study period