Research On Key Quality Control Technology In Mass Production Of Soymilk And Tofu

In production of soybean products enterprise, each of the sessions has an important impact on the quality of product. We researched the production process of tofu, the formula of soymilk, equipment and pasteurization packaging, as well as the storage of fried bean curd, and our purpose is providing theoretical and practical guidance for the enterprise to optimize production quality control system.For optimizing the production process parameters of tofu, we investigated the texture of tofu on the condition of several pulp separation equipment and different kinds of coagulants; for optimizing the formulation of soymilk, we analyzed the role of carrageenan in stabilizing soymilk and applied sensory evaluation to the taste sensory of soymilk; we compared the sterilization efficiency of different pasteurization methods, and measured the temperature curve in the pasteurization cooling process of tofu, and analyzed how different sizes of tofu boxes effect pasteurization efficiency; and more, we studied the storage of fried bean curd by vacuum package with N2 and CO2. The main results showed as follows:1. The addition amount of carrageenan influences the fluid properties of soymilk. 30mg carrageenan couldn’t stabilize soymilk, however adding 60mg, carrageenan and soy protein form weak gel; 45mg carrageenan could to stabilize 150mg calcium, while soymilk obtained good sensory evaluation.2. Blending time and addition of MgCl2 as well as addition amount influence the hardness and yield of tofu. The longer the blending time is, the higher the hardness of tofu is, and the lower the yield of tofu is, on the contrary, the more uniform the voids are. When the blending time were 0.7s,09s,1.8s and 2.6s, respectively, the hardness values were 6.5, 7.4,8.2 and 9.2, while the yield were 39.1LB,29LB,27.8LB and 25.6LB. After comprehensive comparison,0.9s blending time is better. When the addition amount of MgCl2 were 15.8g,23.7g,31.6g and 39.5g, respectively, the water loss rate of tofu were 57.2%,59.3%,61.3%and 57.1%, the hardness values were 1.5,5.8,7 and 8.4. Therefore, we choose 0.9s blending time and 31.6g addition amount of MgCl2 as final parameters in the production of tofu.3. By centrifugal experiment and sensory evaluation, the biaxial coextrusion pulp separation machine and the roller pulp separation machine in the production of tofu were compared. In the biaxial coextrusion pulp separation machine, the smaller particles were from pulp into soymilk due to pressure, thereby affecting the taste of tofu, so the machine does not apply to the production of tofu.4. Soymilk was sterilized in different conditions of 90℃,95℃ of spray type and 90℃ of immersion type. The immersion pasteurization could make soymilk rise to 81℃ within 10 min, and compared to the spray pasteurization, it has higher bactericidal efficiency and can shorten pasteurization time. It was obtained that the temperature curve of in the pasteurization cooling process of boxed tofu, which provided a basis for optimization of pasteurization process. It was analyzed that the pasteurization models of tofu boxes with different sizes, to achieve pasteurization requirements, the Model 43 tofu box with 3 cm height required for the shortest time, while the Model A28 tofu box with 6cm height required for the longest time.5. The fried bean curd packaging by vacuum with CO2 has better storage effect. After one month cold storage, the total number of colonies in tofu was 50CFU/g, but the CO2 in the packaging bag dissolved in fried bean curd and affect the taste of fried bean curd.