An Analysis of TDT and Arrhenius Methods for Handling Process and Kinetic Data

Thermal process calculations generally involve first order reaction kinetics which have been commonly described by the thermal death time (TDT) method in the field of food science but would normally be evaluated by the more conventional Arrhenius approach in most other fields. The relationship between these two irreconcilable approaches is examined conceptually and mathematically in terms of temperature dependence and their use for process time predictions. The errors associated with interconversion of E a and z were shown to be functions of both selected reference temperature and the temperature range used. Good conversions of literature data with minimum error were obtained by substituting the limits of the experimental range over which kinetic data were obtained for T min and T max in the relationship: E a = 2.303 T min T max /z. Although there is no perfect solution to these two conceptually different approaches to handling kinetic data and no proof as to which one is better, the approach of using the experimental temperature range limits produces good results.