Pectinase formulations from Aspergillus niger, are commonly used in fruit juice clarification. The effect of moderate temperature (42.4-62.4 degrees C) at pressures that stabilize a pectinase formulation (200 and 300 MPa) was studied. The rate of viscosity reduction of pectin solutions increased with temperature with a maximum of 0.0960 +/- 0.0108 Pa-1 s(-2) at 62.4 degrees C and 300 MPa which represents a 2.6-fold increase in rate of viscosity reduction relative to the recommended conditions of 45 degrees C and 0.1 MPa. Negative apparent activation volumes of -0.22 +/- 0.18 to -5.21 +/- 0.39 cm(3) mol(-1) indicate that pressure favored the increase in the rate of viscosity reduction with pressure having the greatest effect at 57.1 degrees C. Apparent activation energies of 27.7 +/- 0.7 to 42.4 +/- 11.3 kJ mol(-1) K-1 indicate that temperature had greater effects at high pressure (200-300 MPa) than at atmospheric pressure (15.0 +/- 4.4 kJ mol(-1) K-1). (C) 2014 Elsevier Ltd. All rights reserved.