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Updated: Aug 22, 2026

Measuring Enzymatic Stability by Isothermal Titration Calorimetry
Published on: March 26, 2019
Development characterization and use of a high-performance enzymatic time-temperature integrator for the control of
Yann Guiavarc'h1, Ann Van Loey, François Zuber
1Laboratory of Food Technology, Department of Food and Microbial Technology, Faculty of Agricultural and Applied Biological Sciences, Katholieke Universiteit te Leuven, Kasteelpark Arenberg 23, B3001 Leuven, Belgium. yann.guiavarch@agr.kuleuven.ac.be
Abstract:
A small sized single-component enzymatic time temperature integrator (TTI) was developed. It consisted of glass beads coated with Bacillus licheniformis alpha-amylase (BLA) and stabilizing additives in a dehydrated form. Post heating residual enzymatic activity was used as a response property of the TTI. Under isothermal conditions, different batches of the system were characterized by z(TTI)-values around 13.5 degrees C in the temperature range 100-130 degrees C as well as by their ability to provide a response within 5 min after thermal processing. When used under non-isothermal conditions in a model food (silicone spheres), the system allowed to measure process-values (zTTI)F(121.1 degrees C) up to 60 min with an average error of 10.9%. The capabilities of the system were validated in a real solid/liquid food matrix sterilized by retorting. The combination of F(TTI)-values with heat transfer simulations based on finite difference calculations allowed for the determination of process values, which evaluated actual process-values (10 degrees C)F(121.1 degrees C) up to 90 min with an average error of 11.4%. The good performances of the system as well as its easiness of preparation and use, make the latter a valuable biological device for thermal process assessment.
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