Measurement and Modeling of Thermal Conductivity of Frozen Surimi
D. Kovacevic, Z. Kurtanjek
Faculty of Food Technology and Biotechnology, The University of Zagreb, Pierottijeva 6, 41 000 Zagreb, Croatia
Received June 14, 1994
Accepted February 28, 1995
A design of a system for measurement of thermal conductivity of food by the method of unsteady response from a line heat source is presented. The method is applied for determination of dependence of thermal conductivity of frozen surimi on temperature and cryoprotectant concentration. Measurements were performed in lite temperature range from -25 ºC to +5 ºC. A mathematical model is developed and it is proven that response from a line heal source is defined by the first order exponential integral function E1(x). The estimated parameter is present in the model as a part of the boundary condition. Data are obtained from responses induced by impulses in the power range 2.25 - 4.2 W m-1, sampled with an AID converter with the frequency of 3.5 kHz, and are analyzed in the linear range by the Ieast squares method. The effect of cryoprotectant Poly-dextrose, added in the mass fraction range 0-12% was studied. Data are modeled by the Schwartzberg's model and validated by statistical analysis.
Part of this paper was presented at the 2nd Croatian Congress of Food Technologists, Biotechnologists and Nutritionists, Zagreb, June15-17,1994