Abstract
Summary: The values for thermal inactivation of pectinesterase in mandarin orange juice were F197.4197.5= 1.00 and D197.520.6= 0.54 min at pH 3.6 and F201.517= 1.00 and D2015.518.2= 0.438 min at pH 4.0. the F values were equivalent to 1.85 D at pH 3.6 and 2.28 D at pH 4.0. A 2D process at pH 3.6 and 2.5 D process at pH 4.0 are recommended in the commercial pasteurization of juice.A viscosity procedure described is more sensitive than the jelly test for determining the thermal inactivation of pectinesterase.