Numerical simulation of the commercial tuna thawing, precooking and cooling process.

摘要

This research occurred in three phases. First, the thermal properties of frozen, raw, and cooked tuna were determined. Second, a mathematical model was formulated for each of the three processes. Finally, commercial finite element (FEM) software was used to obtain the final solution.; Differential Scanning Calorimetry was used to obtain specific heat, heat of fusion, and protein denaturation temperatures of raw skipjack tuna. Statistical analysis showed there was no significant difference between specific heat of loin meat (3.536 kJ/kgK), red meat (3.505 kJ/kgK), and viscera (3.446 kJ/kgK). There were significant differences between the backbone (2.263 kJ/kgK) and loin meat, backbone and red meat, and backbone and viscera specific heat values. The protein denaturation temperature of loin meat was higher than that of red meat. Thermal conductivity values of raw skipjack tuna over a range of temperatures were determined by the line source heat probe method. There was no significant difference between the thermal conductivity of raw loin meat (0.57 W/mK) and viscera (0.56 W/mK). In general, thermal conductivity increased with temperature.; The finite element method was used to solve a two dimensional of the heat and mass transfer in tuna by breaking it into three regions, muscle, backbone, and viscera. Commercial preprocessor software, GAMBIT 1.1, and finite element software, FIDAP 8.52, were used for the solution of this model for tuna undergoing the thawing, precooking, and cooling operations. The validity of the model was tested via comparison with experimental data collected in a commercial processing facility and a pilot plant. Good agreement between the simulation and experimental results were obtained.