Multi-agent simulation of doughnut deep fat frying considering two domain heating media and sample flipping.

Two domain heating media and sample flipping during processing were considered when developing an agent-based model to explain coupled heat and mass transfer phenomena during deep fat frying of doughnuts. The model was validated by comparing the moisture content, oil content and temperature profiles obtained from the experimental results with those obtained from the model. Results of this study showed that the water content of crumb raised to 60% (based on dry weight) whereas, it decreased to less than 10% in the case of doughnut crust during deep fat frying. Simulated profile of oil penetration illustrated that the oil content of different parts of crust were not equal and were affected by frying temperature and crust structure. In general, as the surface of doughnut (a porous material) was heated from the surface, evaporation zones were formed in the thinner parts of the crust and gradually formed oil penetrating areas. Moreover, experimental and simulated data indicated that flipping of samples in the middle of processing time had an important effect on heat and mass transfer during frying. Variation of thermophysical properties in each part of doughnut had a unique behavior. The changes in the density, specific heat capacity and thermal conductivity of crumb followed a sigmoid pattern; whereas, a dominant falling rate period with some variations was observed in crust. Moreover, any changes in moisture content and temperature of crust occurred faster than the crumb. The output of simulation was in a good agreement with the experimental data. With the power of simulation now available for design, the results of this study greatly improve the design of fried foods and frying processes.