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Corn is one of the main alimentary crops in our country with wide cultivated area. Corn is a healthy product in roughages which not only contains carbohydrate, protein, fat, carotene, but also contains glutathione, fiber, calcium, magnesium, selenium and vitamin E and so on. The corn have sweet flavor, is neutral in nature and can adjust the body, invigorate stomach and prevent and cure constipation, enteritis, intestinal cancer, etc. The corn spermoderm and the corn protein powder are the main by-products of corn processing industry. The corn dietary fiber from corn spermoderm has the physiological effect of resisting constipation, lowering blood fat and reducing cholesterol. Corn fine powder which was Rich in functional active corn peptides was obtained by casting off fat and impurity and modification of the corn protein powder. Now only a few corn was staple food, most were used for feed and industrial raw materials because of the high viscosity inelastic of corn dough, and bad edibility and low processing performance of corn flour. The modified corn flour has many defects such as excessive elasticity, which goes against production of kinds of corn food. In this study, corn flour were modified effectively by advanced extrusion technology, to improve processability and edible degree of corn flour, be made use of grain food processing partly or in full instead of wheat flour and then be mixed with the corn dietary fibre and corn gluten meal to produce bread. The product was in rich nutrition, had the best sense organ quality, was asepsis and harmless to human body and had important physiological functions, such as reducing weight. The research is conducive to make full use of food resources, solve grain safety problems, and conforms to the national food policy.The main research results are as follows:1. Modify corn flour by twin-extrusion technology in high temperature and high pressure, and determine the optimum condition. When the extrusion temperature was 135.9℃, the water content of material was 47.6%, the screw speed was 32.5Hz, the springiness value of modified corn dough was 0.113811.2. Modify corn flour by the single extrusion technology, and determine optimum condition with circular extrusion hole. When the extrusion temperature was 151℃, the water content of material was 33.3%, size of material was 61.6 mesh number. The springiness value of modified corn dough was 0.12917.3. Determine the optimum condition of the single screw extruder with square extrusion hole:the extrusion temperature 149.6℃, the water content of material 42.6%, size of material 60.6 mesh number. After process parameters was revised, extrusion temperature was 150℃, the water content of material was 43%, and size of material was 60 mesh number. In the conditions, the modified corn flour dough property has the best value:Hardness 3037.697, Adhesiveness-2.162, Springiness 0.136, Cohesiveness 0.259, Gumminess 769.195, Chewiness 98.484, Resilience 0.075.4. Compare the results of twin-extrusion technology with the single extrusion with circular extrusion hole and with square extrusion hole. The single extrusion with square extrusion hole was the best method. When the extrusion temperature was 150℃, the water content of material was 43%, size of material was 60 mesh number(0.246mm), the theoretical springiness value of modified corn dough was 0.136.5. The best formula of corn weight-reducing bread was determined. When the corn flour was 55%, the modified corn flour was 15%, the corn dietary fiber was 10%, the modified corn gluten meal was 4%, bread improver was 2%, yeast was 2%, soft sugar was 5%, egg was 4%, corn oil was 3%, salt was 1.2%, weight-reducing factor was 1%, the bread had the best quality and good corn flavor.6. Functional experiments:Use of corn weight-reducing bread bred mice, obese mice had a weight of decline and body fat number was significantly reduced compared with the controller. The corn weight-reducing bread had effect reducing weight to obese mice.
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