Influence of pH on the Thermal Inactivation Kinetics of Horseradish Peroxidase in Aqueous Solution

Authors: Lemos M.A.¹; Oliveira J.C.²; Saraiva J.A.³

Source: Lebensmittel-Wissenschaft und-Technologie, Volume 33, Number 5, August 2000 , pp. 362-368(7)

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Abstract:

The thermal inactivation of horseradish peroxidase in aqueous solution was studied in the pH range of 3.0 to 12.5, at temperatures ranging from 40 °C to 95 °C. The data were well fitted by a double exponential model. The enzyme showed highest stability around neutral pH and the stability was particularly decreased above pH 11. The z value of the less labile fraction at pH 11.5 to 12.5 (temperatures from 40 to 65 °C) and of the more labile fraction at pH 3–4 (temperatures from 65 to 85 °C) were close to 10 °C, making these systems suitable as time-temperature integrators for assessing microbial lethality in thermal processing of low-acid foods, particularly if they can be stabilized further without affecting their low z-value. Copyright 2000 Academic Press

Keywords: enzyme inactivation; kinetic modelling; protein thermal denaturation

Language: English

Document Type: Research article

Affiliations: 1: Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr António Bernardino de Almeida, Porto, 4200, Portugal 2: Department of Food Science and Technology, University College Cork, Cork, Ireland 3: Department of Chemistry, University of Aveiro, Campus de Santiago, Aveiro, 3810-193, Portugal

Publication date: 2000-08-01