Performance Comparison of Three Microwave Susceptors on Some Quality Characteristics of Cake During Baking Process

The present study has introduced a mixture of seven nano-metal oxides (WO2, TiO2, Al2O3, SiO2, Y2O3, ZrO2, and MgO) as a MicroWave (MW) susceptor to evaluate its effectiveness compared to two others conventional susceptors on temperature distribution, weight loss, and quality characteristics of cakes baked in a 900-W MW oven. Based on the results, the highest processing time was related to cakes baked without any susceptor. The operation time varied depending on the susceptor used; therefore, the cake baked in the MW with the nano-metal oxides susceptor had the lowest operational time. The final surface temperatures of the samples varied between 181, 160, 140, and 130°C during MW baking with nano-metal oxides, alumina + silicon carbide (Al2O3+SiC), aluminum (Al) susceptors, and without a susceptor, respectively. Therefore, the temperature of the nano-metal oxide susceptor reached higher than 177°C, which was necessary for non-enzymatic browning reactions. The susceptor of nano-metal oxides in MW heating not only changed the surface temperature of the product in contact with the susceptor but also affected other parts of the product. Additionally, the rate of the browning reaction starts low at the beginning of the process, gradually increases, and then decreases towards the end of the process. Furthermore, cakes baked with the nano-metal oxide susceptor exhibited the lowest hardness compared to those baked without a susceptor. In conclusion, the nano-metal oxide susceptor is the most suitable choice for MW baking cakes due to its high level of surface absorption of MW radiation, resulting in increased surface temperature, shorter processing time, and lower hardness.