Mosambi juice was treated with pectinase enzyme at different durations (40-141 min), temperatures (32-49 degreesC), and at various concentration level of enzyme (0.0004-0.0014 w/v%). The effects of the enzyme treatment conditions on various parameters (e.g., apparent viscosity, clarity and alcohol insoluble solid) were studied. The optimum process condition, were determined employing a second-order central composite rotatable design in combination with response surface methodology. Apparent viscosity and alcohol insoluble solid decreased with temperature and enzyme concentration. Clarity of juice increases with temperature and the enzyme concentration. (C) 2003 Published by Elsevier Ltd.