| Taking corn as raw material, the enzymatic wet milling process of corn starch and the properties of enzymatic-milling starch were studied by adding acid protease. The main results were as follows:1. The optimum steeping time of the first steeping of the enzymatic wet milling process of corn starch was 4h.2. During the enzymatic steeping, studied by single factor experiment, we determined the optimum value of each influence factor with starch yield as export index. The results were as follows: the addition of protease is 1000u/g, pH of steep solution is 3.4, steep temperature is 50℃, steep time is 10h.Based on single factor experiment, the optimum technical parameters of enzymatic steeping in the enzymatic wet milling process of corn starch were determined by using quadratic general rotary design. According to the experimental results, by statistical analysis, we got the regression equation of starch yield and all influence factors:Y=63.499986-1.826567X1+3.576792X2+0.710167X3+0.879683X4+0.950700X1X2+0.437550X1X3+0.130575X2X3+0.483363X1X4+0.391738X2X4+0.006887X3X4-2.975176X12-2.287913X22-1.767876X32-0.514788X42By analsing the regression equation and the test experiment, we obtained the optimum technical parameters of the enzymatic steeping: the addition of protease is 989u/g, pH of steep solution is 3.58, steep temperature is 50.57℃, steep time is 8.33h.3. There was no significant difference between enzymatic-milling process and the traditional corn wet milling process in starch yield. The properties of enzymatic-milling starch that had been extracted were studied systematically. The difference between the enzymatic-milling starch and common starch is not significant. It can take the place of common starch completely.4. The research could cut down time and save capital and energy. And it also could resolve the remain of SO2 in traditional corn wet milling process without avoiding it. For these reasons, there are important significances for starch industry.
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