MEASUREMENT OF THERMAL-DIFFUSIVITY OF POTATO, MALT BREAD AND WHEAT-FLOUR

The thermal diffusivity of three food products, Pentland Dell potato, malt bread and wheat flour, was determined using a thermal diffusivity tube under transient heat transfer conditions by two different methods, the log method and the slope method, both based on the solutions of the Fourier equation. Both methods gave similar results for potato, 1.30 x 10(-7) and 1.44 x 10(-7) m2 s-1, flour, 1.00 x 10(-7) and 1.04 x 10(-7) m2 s-1, but different results for bread, 1.17 x 10(-7) and 2.56 x 10(-7) m2 s-1. The values were compared with a prediction model and with previously documented values. The measured values for potato and flour were found to be close to those calculated by the prediction model. The value for bread, calculated by the log method, was also close to the predicted value, but its thermal diffusivity calculated by the slope method was close to literature values.