J. Saraiva et al., INACTIVATION KINETICS OF HORSERADISH-PEROXIDASE IN ORGANIC-SOLVENTS OF DIFFERENT HYDROPHOBICITY AT DIFFERENT WATER CONTENTS, International journal of food science & technology, 31(3), 1996, pp. 233-240
The thermal stability of horseradish peroxidase suspensions was studie
d in three organic solvents of different hydrophobicity (dodecane, oct
ane, and I-octanol) at three different water contents (14.1, 55.3 and
256.2 mg water g(-1) dry protein). In these conditions, the enzyme is
much more stable than in aqueous solutions (inactivation temperatures
were in the range of 125-150 degrees C). The enzyme showed a similar s
tability when in the presence of organic solvents, compared to the enz
yme in a solid matrix without organic solvents with the same water con
tent. The inactivation kinetics was well described by assuming the exi
stence of two iso-enzymes, both inactivating according to a first orde
r model. The lowest value for the z-value of both fractions (around 15
degrees C) was obtained at the higher water content studied. The use
of solvent and water content variables should be adequate to develop t
ime-temperature integrators to monitor thermal processes at 100-140 de
grees C.