Umbu (Spondias tuberosa Arr. Cam.) diluted pulp, at mass ratio of one part of pulp to two parts of water, was microfiltered in a pilot plant containing a 0.2 mu m polypropylene membrane. A clarified juice free of pulp and with low pectin content was obtained. Effects of enzyme treatment (0-100ppm), crossflow velocity (4-6 m/s) and transmembrane pressure (0.5 x 10(5)-1.1 x 10(5) Pa (0.5-1.1 bar)) were evaluated using permeate flux and flux resistances (total, due to fouling and polarized layer formation) as parameters. Crossflow velocity was the major variable responsible for flux increase, since it reduced polarized layer. Enzyme treatment also presented a positive effect. On the other hand, transmembrane pressure increased fouling and did not influence permeate flux in most cases, except when no enzyme was added and high velocity was applied, in which flux was reduced. (c) 2006 Elsevier B.V All rights reserved.