Effect Of Ohmic Heating On Electrical Conductivity And Rheological Characterization Of Pork

The food's electrical conductivity is one of the factors that affect producing calories inside of the food, so it takes very important part in the research and development of ohmic heating technique. In order to make good use of the ohmic heating technique, it's very necessary to study the relationship between electrical conductivity and temperature and to study the affect of electric conductivity to heating rate. The main purpose of the research of food processing technique is to make the food's quality better, so studying the affect of ohmic heating to food's quality is very necessary. In order to find out the technics of meat ohmic heating, we must study the electric conductivity when the meat is heated, and also need to study the effect of ohmic heating on food's Theological properties.Tow parts were includes in this paper: the first part was finding out the effect of ohmic heating to meat specimen's electric conductivity, the other is studying the affect of ohmic heating to specimen's rheology characteristic. The main content includes the following parts:1. A set of the ohmic heating setup was developed, which includs a contact ohmic heating test setup and a no-direct-contact ohmic heating test setup, and a data acquiring system, by which the parameters of the voltage, the current, the temperature and its distribution were measured during the samples were heated. The results showed that the system can heat the meat uniformity and quickly, and the voltage, the current, the temperature can be recorded by the Data acquiring System.2. The pork sample was cooked by the contact ohmic heating setup and the no-direct-contact ohmic heating setup. The results showed that the curves of the electrical conductivity of the meat heated with the both setups changing with temperature are almost the same. The electrical conductivity that was measured in the no-direct-contact ohmic heating setup is slightly smaller than the one in the contact ohmic heating test setup when the temperature was between 60℃~100℃, that's because the influence of the NaCl solution.3. The changes of the electrical conductivity of the muscle and the mincing samples, by heated with the contract ohmic heating test equipment, with the temperature, and the influence of the different electrical field strength to meat's heating rate and electrical conductivity were investigated. The resultsshowed that the sample's electrical conductivity gradually increases with the temperature increasement, the entire tenderlion's electrical conductivity is a little bit higher than mincing meat's when the fibre was parallel to the electric field strength and the increasement in the entire tenderlion's electrical conductivity is more than mincing's at the same temperature. The results also showed that the electrical field strength has a little bit influence to the electrical conductivity.4. The influence of the different concentration of the NaCl solution to the heating rate and the electrical conductivity by using no-direct-contact heating test setup was explored. The results showed that the higher the concentration of the NaCl solution, the higher the heating rate, and the electrical conductivity measured is also higher.5. The effect of the ohmic heating on the shear strength and compression parameters of the meat samples was studied by using TA-XT2. Compared with the results of the water bath at 100℃. The results showed that the texture of the meat have no obvious differences between the ohmic heating and the water bath and the sample's tenderness can be improved by the heating rate and the heat preservation progress.6. By using analytic sensory evaluation mathod, the tenderness and juiciness of the meat specimens, which were heated by ohmic heating and by traditional heating respectively were evaluated. The results showed that the specimens' tenderness and juiciness have no obvious differences after the specimens were heated by the two ways at the same heating rate.Ohmic heating possesses many advantages, such as heating uniformity, easily to control heating rate, higher efficiency. This thesis proved that meat qualities have no obvious differences which were produced by ohmic heating and traditional way respectively. So, ohmic heating technique should be a popular meat processing technique.