L. Ceci et J. Lozano, DETERMINATION OF ENZYMATIC-ACTIVITIES OF COMMERCIAL PECTINASES FOR THE CLARIFICATION OF APPLE JUICE, Food chemistry, 61(1-2), 1998, pp. 237-241
Different methods for testing Polygalacturonase (PG), pectinesterase (
PE), and pectinlyase (PL) activities were applied to Rohapect DSS (RHD
5) and Pectinol (PAI) commercial enzyme preparations in an apple pecti
n substrate. The viscometric method for PG activity determination was
satisfactory, but foreign proteins could affect the spectrophotometric
determination of PL activity in solutions of enzyme preparations. Alt
hough 50 degrees C was a well-defined breaking point where enzymes rap
idly decrease their activity, rate and range of heat-inactivation were
different depending on the activity assayed. While PG activity showed
two periods of different thermolability, PL was monophasic and highly
sensitive to heat. The pH dependence of the pectic enzyme activities
was also studied over the 3-7 range. (C) 1998 Elsevier Science Ltd. Al
l rights reserved.