Study On Extruding Soybean Meal And Flour For Making Soy Sauce

Compared with the traditional cooking method to process raw materials, extrusion technology used for soy meal and flour pretreatment can achieve the purposes of moderate protein denaturation, starch paste, passive anti-nutritional factors and sterilization,and the purposes of improve protein digestibility and amino acid production rate. The current situation of low utilization of raw materials in our soy production industry allows this technology a higher market value. The main aim of this study is to optimize the technology of extrusion process, koji process and fermentation process and provide technical support to this technology is further used for the production of soy sauce practice.We get the following conclusion through test:Make protein digestibility as main indicators, and choose NSI value protein, starch gelatinization and density as assist indicators at the same time. Select five test factors include the proportion of flour, the moisture of material, the temperature of the barrel, the diameter of the die nozzle and the speed of the screw to make test. The optimum parameters of extrusion process are as follows:the proportion of flour is 14%, the moisture of material is 23%, the temperature of the barrel is 135℃, the diameter of the die nozzle is 10mm, the speed of the screw is 200r/min. Under this condition the protein digestibility is 87.21%, the NSI value protein is 43.25%, the starch gelatinization is 98.26%, and the density is 473.2kg.m-3.Make neutral protease activity as main indicators, and choose alkaline protease activity, amylase activity and glucoamylase activity as assist indicators at the same time. Select four test factors include the temperature of koji, the proportion of bran, the moisture of koji, and the time of koji to make test. The optimum parameters of koji process are as follows: the temperature of koji is 30℃, the proportion of bran is 30%, the moisture of koji is 100%, the time of koji is 60h. Under this condition the neutral protease activity is 1920U/g,the alkaline protease activity is 786U/g,the amylase activity is 587U/g,and the glucoamylase activity is 31.87U/g.Make the utilization of nitrogen as main indicators, and choose the content of amino nitrogen, total acid, the value of pH, color ratio and red indices as assist indicators at the same time. Select three test factors include the ratio of brine, the temperature of fermentation, the time of fermentation to make test. The optimum parameters of fermentation process are as follows:the ratio of brine is 80%, the temperature of fermentation is 46℃, the time of fermentation is 15d. Under this condition the utilization of nitrogen is 86.06%, the content of amino nitrogen is 0.7934g/100mL,the total acid is 0.926 g/100mL, the value of pH is 5.58, the color ratio is 8698BEC and the red indices is 5.10.