Research On The Freezing Process And Freezing Mathematical Model Of Frozen Tofu

In recent years, the nutritional value of soybean and soy products received growing recognitionfrom Chinese and foreign experts. Particularly tofu represented China's traditional bean products onhuman health effects attracted the eyes of the world food nutritionists. Frozen tofu as a traditionalsoybean food with a long history, not only more easily store and transport than bean curd, but also inthe freezing process, soyabean protein occurred freezing denaturation, that made frozen tofu porousnetwork structure and tasty. However, domestic production of frozen tofu also limited to family orindividual workshop production. The sanitation, technology and quality are all poor.In response to these problems, this study focused on the freezing process of frozen tofu, andestablished a freezing mathematical model. Specific work as following:①We finished four groups of single-factor experiments and a group of orthogonal experiments, gotthe best freezing processes is, in -10℃, freezing for 3h, and then in -3℃maturing for 21 days. Andintegrated into springiness and aperture structure, the freezing temperature need to be controlled in the-15℃～-10℃range.②Orthogonal experimental data indicated that the maximal factor affecting the quality of frozentofu was maturing time, followed by maturing temperature, and again for freezing temperature, andfreezing time minimal impacted on the quality.③Detecting results by TMS-2000 Food Texture Analyzer showed that, the springiness of frozentofu reduced with maturing temperature reduced; and increased with maturing time increased.④We made a theoretical analysis of freezing process, established three-dimensional freezingmodel and did numerical simulation by finite difference method and computer programming tools"Visual Basic". Visual pictured of the temperature time variation of various locations in frozen tofu,during the freezing process, and was accurate at the complete time.⑤Through certification experiments proved the reliability of mathematical models, andexperiments using least square method determined the surface convective heat transfer coefficient h(J/m~2·K) of frozen tofu in the conditions of experiments.⑥Analyzed wind velocity, size of frozen tofu, freezing temperature and other factors affecting thefreezing complete time, using the established freezing mathematical model. And further more weforecasted freezing status in other different conditions, thus facilitated guiding further large-scaleproduction and reducing energy consumption.