Effects of Fruit Maturity and Processing Method on the Quality of Juices from French-American Hybrid Wine Grape Cultivars

Abstract

This study was conducted to examine the effects of grape maturity and processing method on the quality of juices from four French-American hybrid wine grape cultivars (Seyval, Vidal, Aurore, and Chancellor). The flavor of juices from more mature grapes (soluble solids:acidity ratio of 20 - 30, pH 3.45 - 3.60) was rated higher than the flavor of less mature grapes (soluble solids:acidity ratio of 13 - 19, pH 3.25 - 3.40) initially and after five months storage at 37°C, but maturity had no significant effect on the color of the juices. Heating grapes to 60°C before pressing or leaving juice and skins in contact for 24 hours before pressing rather than pressing immediately produced juices with higher pH and superior color initially. The processing method had little effect on the flavor ratings of the white cultivars initially, but the Chancellor juices with 24 hours of skin contact had higher flavor ratings than the Chancellor juices that were pressed immediately. Heat extraction was detrimental to the flavor and color of juices from the three white cultivars after storage, but it improved color and flavor stability of the red cultivar, Chancellor.