International journal of food science and technology vol:31 issue:3 pages:233-240
The thermal stability of horseradish peroxidase suspensions was studied in three organic solvents of different hydrophobicity (dodecane, octane, 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 stability when in the presence of organic solvents, compared to the enzyme in a solid matrix without organic solvents with the same water content. The inactivation kinetics was well described by assuming the existence of two iso-enzymes, both inactivating according to a first order 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 time-temperature integrators to monitor thermal processes at 100-140 degrees C.