Combined use of two single-component enzymatic time-temperature integrators: application to industrial continuous...

Two original, highly dehydrated, small single-component enzymatic time-temperature integrator (TTI) systems, TTIL and TTIs, were prepared. Their z-values were 13.9 and 16.4 degrees C, respectively, and they were based on Bacillus licheniformis alpha-amylase and Bacillus subtilis alpha-amylase, respectively. The isothermal calibration of these two TTIs revealed that (i) they can be used in the temperature range of 100 to 140 degrees C, (ii) results can be read within 5 min, and (iii) they can be used individually for the measurements of process values 13.9 degrees CF121.1 degrees C and 16.4 degrees CF121.1 degrees C up to 98 min and 85 min, respectively. Because these two TTIs have different z-values above 10 degrees C, they could be used in combination with the multicomponent TTI concept to estimate process values 10 degrees CF121.1 degrees C inside particles of a solid or liquid food submitted to rotary processing. Raviolis in tomato sauce sterilized in an industrial-scale reel and spiral continuous retort were examined in this study. Two methods, based on the combination of a one-dimensional explicit finite difference heat-transfer model with the experimental responses of the TTIs, were used to take into account the possible deviations in evaluation of 10 degrees CF121.1 degrees C values. A process value 10 degrees CF121.1 degrees C of 23.6 min with a standard deviation of 1.5 min was determined inside raviolis using the multicomponent TTI approach, and a process value 10 degrees CF121.1 degrees C of 33.6 min with a standard deviation of 1.5 min inside the sauce was calculated from the temperature recording data.