ANALYSIS OF THE INACTIVATION KINETICS OF FREEZE-DRIED ALPHA-AMYLASE FROM BACILLUS-AMYLOLIQUEFACIENS AT DIFFERENT MOISTURE CONTENTS

The thermal inactivation kinetics of freeze-dried alpha-amylase in a s olid matrix was studied at water contents ranging from 1.5 to 23.9 g w ater per 100 g dry solid. These conditions were obtained by equilibrat ion in dry environments, with water activities ranging between 0.11 an d 0.88. Isothermal inactivation experiments in the range 135 to 150 de grees C were performed Results were analysed with both the Bigelow and Arrhenius models. It was concluded that there was no statistical sign ificance to suggest that the rr ater content influenced the kinetic pa rameters An activation energy of 128 kJ/mol and pre-exponential factor with a logarithm of 33.9 described all the results well.