Thermal Inactivation of Asparagus Lipoxygenase and Peroxidase

Thermal stability of lipoxygenase (LOX) and peroxidase (POD) in fresh asparagus tips and partially purified asparagus LOX and POD were compared. In all cases, heating at 50, 60 and 70°C resulted in higher percentages of residual LOX activity than POD activity. Inactivation of LOX followed first order kinetics while inactivation of POD followed a biphasic curve. Activation energies for thermal denaturation of the partially purified enzymes were 47.5 kcal/mol for LOX and 41.9 kcal/mol for POD.