| China has very rich freshwater fish resource, but consumption has a low growth. However, Surimi processing using a small package from surimi products greatly improved the value of freshwater fish. At the same time, surimi products with soy protein can improve the nutritional content of surimi and meet the different needs of animal and plant proteins to people. Surimi processing using a small package from surimi products greatly improved the value of freshwater fish. Microwave heating as an efficient, energetic heating method in the processing of aquatic products has aroused more and more attentions.In order to research the temperature distribution and formation mechanism of the breaking force distribution of freshwater surimi products during the process of microwave heating, silver carp of 78% moisture content was the experimental object and the different proportion components experimental samples was to added soybean protein isolate emulsion in surimi. By investigating different microwave heating time 60s,90s,120s and different radius of cylindrical surimi and its compound 11mm,18mm,22mm, the temperature distribution, breaking force and gel formation mechanism were studied. At the same time according to the dielectric properties and thermal properties, finite element method (FEM) was applied to build a two-dimensional mathematical model to predict the temperature distribution of surimi and its compound microwave heating through electromagnetic fields on the microwave heating process and temperature field theory analysis. The comparison of numerical value and experimental value demonstrated that mathematical model can well predict the temperature distribution of surimi and its compound microwave heating and reveal the internal mechanism of the temperature distribution theoretically improve the temperature distribution of surimi products during the microwave heating process to, optimize product quality and provide a theoretical basis, to reduce or avoid the laborious and time-consuming tests.Through the above, following conclusions were obtained:(1) The sample size has a significant impact on the temperature distribution in surimi products. A small size (R = 11mm) was performed core high temperature and uneven temperature distribution; the core temperature of a large size (R = 22mm) was low and large temperature difference between hot-cold spots; intermediate size (R = 18mm) had more uniform temperature distribution.(2) The influence of microwave heating time on the temperature distribution mainly displayed that with the increase of heating time, the section temperature gradually increased; The radial temperature difference of The two size samples (R=11mm and R=22mm) increased and the temperature distribution was more and more uniform with the increase of heating time. The radial temperature distribution of the sample (R=18mm) had no significant change and axial temperature distribution decreased first and increased gradually with the increase of heating time.(3) The difference between the content of SPI emulsions and the one-dimensional radial temperature distribution of the different points performed that the single surimi showed the highest temperature. With the addition content of SPI emulsions increasing, the temperature increased, also to the section temperature diffenence.(4) The sample size, heating time and SPI emulsion content also have an influence on the breaking force. By analyzing gel formation thermodynamics of surimi microwave heating, the effect of sample size and heating time on breaking force internal mechanism was temperature had a great influence on the breaking force, which temperature and breaking force were positively correlated. SPI emulsion content on the major impact of the breaking strength was two different types of protein interactions by soy protein, oil content and other factors.(5) The use of two-dimensional finite element method to establish mathematical model of temperature distribution, calculation value and experimental value showed good agreement, indicating the reliability of mathematical models; At the same time through analysis the mathematical simulation, the effect factors of temperature distribution whose sample size,heating time and the content SPI emulsion were theoretically analyzed.(6) During the data analysis process, dielectric and thermal properties were measured practically and empirical formula was established, which made up of the data gaps of dielectric and thermal properties between freshwater fish and its compound, provided accurate parameters for studying engineering calculation of others heating process and also to the process equipment designing. |
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