Kinetic behaviour and thermal inactivation of pectinlyase used in food processing

Kinetic properties and thermal inactivation of pectinlyase (PL) were assayed in commercial pectinase preparations (Rapidase C80, Pectinase CCM, Pectinex 3XL and Grindamyl 3PA) by using apple pectin as substrate. The PL activity of Rapidase C80 showed substrate inhibition, while the other enzyme preparations followed typical Michaelis–Menten kinetics. The optimum pH and temperature values for PL activity lay within the range of 5.5-6.5 and 35-40 °C, respectively. PL was heat-inactivated with simple first order kinetics. With respect to this, thermodynamic activation parameters ((delta)H^#, (delta)S^# and (delta)G^#) using a non-linear Arrhenius plot were calculated. The Pectinase CCM and Pectinex 3XL PL showed a half-life (t1/2) at 50 °C of 2.0 min and 11.8 min, respectively.