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This study investigated the effects of microwave-assisted freezing on the quality attributes of button mushrooms (Agaricus bisporus). Four levels of microwave power (0, 10, 20, 30%) were applied to the mushroom samples during freezing. The quality attributes of the frozen and thawed mushrooms were then evaluated. The results suggested that higher microwave power produced the smaller and more uniform ice crystals. Moreover, the browning index of the mushroom samples increased with increasing microwave power. The textural properties (hardness) of the mushrooms were also affected by the microwave power, showing higher values as the power increased. Furthermore, the ratio of the microwave operating system's power to the freezer power was low and approximately 20% at the highest power level. Therefore, these findings confirm the potential of microwave-assisted freezing for reducing freeze damage to mushroom tissue and, thus, provide frozen mushroom with a better texture. [ABSTRACT FROM AUTHOR]

A model for simultaneous heat and mass transfer during the cooking process of frozen hamburger has been developed, using a modified form of Darcy's law to describe the capillary flow of moisture and Fourier's second law in cylindrical coordinates to describe the heat transfer. The effects of cooking time (0 to 12 min), cooking temperature (140 to 160 °C), and patty thickness (10 to 14 mm) during the hamburger cooking process on temperature profile, moisture content, and inactivation kinetics of Salmonella bacteria were investigated. The results showed that the predicted temperature and moisture values are in good agreement with the measured data. Due to the low convective heat transfer coefficient in the upper part of the sample at the beginning of the cooking process, non-uniformity in temperature was observed, which was resolved by flipping the hamburger and resulted in a reduction in cooking time. In addition, an increase in the heating temperature results in an increase in the rate of evaporation and moisture loss from the hamburger patty. The simulation results showed that at a cooking temperature of 140 °C and a patty thickness of 14 mm, all points of the hamburger will not achieve a 12D reduction of Salmonella and there is a possibility of salmonellosis under these conditions. [ABSTRACT FROM AUTHOR]