Measurement of thermal diffusivity of granular food materials

In this study thermal diffusivity of two varieties of Triticum durum wheat and a wheat product, bulgur, is determined at different moisture contents and the results are compared with predictive models as well as with literature values. Thermal diffusivity is measured with transient heat conduction method which consists of placing a cylindrical sample in a constant temperature environment and recording the temperature at the center of the sample with respect to time. If the surface convective resistance is negligible, thermal diffusivity is determined from the time-temperature history and the dimensions of the sample. The measured thermal diffusivity values ranges between 8.92x10(-8) and 11.43x10(-8) m(2)/s for Eregli, 8.76x10(-8) and 10.78x10(-8) m(2)/s for Saruhan and 8.28x10(-8) m(2)/s for Bulgur. The results are in good agreement with literature values and close to Riedel and Martens models. (C) 1997 Elsevier Science Ltd.