Response of a Hard-to-Press Vitis rotundifolia Cultivar and a Hard-to-Clarify Euvitis Hybrid to Commercial Enzyme Preparations

¹ Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL 32611.

A hard-to-press white grape cultivar, Dixie (Vitis rotundifolia), and a hard-to-clarify white cultivar, Stover (Euvitis hybrid), were treated with three concentrations of a commercial pectinase preparation and a pectinase-cellulase-hemicellulase preparation in an effort to improve press yields and/or the degree of settling. Both the standard pectinase preparation and the pectinase-cellulase-hemicellulase preparation were effective in increasing total press yields and free-run juice from both cultivars. However, the pectinase-cellulase-hemicellulase mixture did not increase settleable solids or total suspended solids in the Euvitis hybrid to nearly the extent of the pectinase preparation. The pectinase-cellulase-hemicellulase preparation was slightly more effective in increasing free-run yields than was the standard pectinase preparation.

Key words: pectinase, cellulase, hemicellulase, press yield, juice clarification

Submitted on March 10, 1988