Thermal Kinetic Parameters of Thiamin in Wheat Flour at Temperatures Higher than 100 degrees C

Kinetic parameters for thiamin degradation were obtained using 2 high-temperature heating methods: (1) atmospheric pressure (AP) with moisture correction and (2) controlled pressure (CP). At AP conditions, 33.3% dry basis (db) moisture wheat flour with 0.35% (db) thiamin was heated in thin steel cells isothermally at 145, 160, and 172 degrees C. To obtain the moisture correction factor, a constant-moisture study was conducted at 80 C using 6 moisture contents (6.1% to 36.9%). At CP conditions, flour at 19%, 28.2%, and 33.3% (db) moisture in double-seamed cans was heated in a CP steam retort at 129 degrees C. For the AP method, the corrected activation energy for 33.3% moisture content was 129.5 kJ/g-mol and reaction rate at 80 C was 3.48x10-4 min-1. Using the CP method, the activation energy and reaction rate were 121.0 kJ/g-mol and 9.69x10-5 min-1, respectively. Results obtained from 2 methods were not statistically different. These results illustrated that the correction method could be used as an alternative for researchers without access to controlled pressure equipment and transient heat transfer software. [PUBLICATION ABSTRACT]