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The influence of water activity on thermal stability of horseradish peroxidase
Author(s) -
HENDRICKX M.,
SARAIVA J.,
LYSSENS J.,
OLIVEIRA J.,
TOBBACK P.
Publication year - 1992
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.1992.tb01175.x
Subject(s) - horseradish peroxidase , chemistry , thermal stability , peroxidase , kinetics , fraction (chemistry) , moisture , enzyme , water content , water activity , specific activity , enzyme assay , chromatography , thermodynamics , biochemistry , organic chemistry , physics , geotechnical engineering , quantum mechanics , engineering
Summary The thermal stability of horseradish peroxidase in the solid state was studied as a function of water activity, from 0.11 to 0.88. At all activities the enzyme was found to be much more stable in the solid state than in solution. Inactivation temperatures were in the range of 140–160°C. Inactivation curves show a biphasic behaviour which can be described by a model assuming two fractions (heat labile and heat stable) with independent first order inactivation kinetics. The labile fraction represents approximately 30% of the total activity. The z‐value for both stable and labile fractions depends on water activity (moisture content) and has a maximum at a w = 0.76 (44.4°C and 43.8°C, respectively).