【作者】 王宏立；

【导师】 张祖立；

【作者基本信息】 沈阳农业大学 ， 农业机械化工程， 2004， 硕士

【摘要】 我国有丰富的大豆资源，年产量约为1500万t，居世界第四位。与其它农作物相比，大豆中含有丰富的蛋白质和油脂，必需的氨基酸、脂肪酸，卵磷脂的含量也十分丰富，是人类的优质食品和动物的优质、高能、高蛋白饲料。近年来，随着我国畜牧业的发展，对蛋白质的需求量在不断增长，但动物蛋白资源有限，不能满足养殖业的需求，必须寻找植物蛋白资源部分替代动物蛋白资源。而植物蛋白资源中大豆蛋白有其独特的优点，将大豆通过挤压膨化加工后，添加到饲料中，可替代豆粕加油脂的传统方法，且取得了良好的饲喂效果。 目前，挤压膨化技术日渐完善。但现有的大豆膨化机结构复杂，尺寸大，操作维护不便且设备的价格较高，不能满足小型企业及个体户、专业户的需求。对现有膨化机改进设计及试验，研制一种结构简单，价格便宜，易于操作，便于维修的、小型螺杆挤压膨化机，用来加工全脂大豆，促进大豆资源的开发和利用。 为了深入研究大豆膨化技术，改善试验设备的功能，本文分析了挤压膨化机的工作原理，对大豆膨化机理进行了初步探讨。膨化试验中，采用单螺杆挤压膨化机，在现有设备的基础上，对其主要工作部件进行了改进设计及试验研究，并综合分析了影响膨化效果的因素。以生产率和度电产量为试验指标，通过单因素试验，考察和分析了不同大豆含水率、不同螺杆转速、不同膨化温度、不同出口间隙对膨化加工的影响，为二次回归试验设计提供依据。 通过三因素五水平的二次回归正交旋转设计，研究了大豆含水率、螺杆转速和膨化温度等因素对度电产量、生产率和膨化压力的影响。通过建立的数学模型，利用二元函数曲面对影响各个指标的主要因素进行了分析，并用有约束非线性优化理论对工艺参数进行了优化，确定了一组最优参数。 针对本试验中存在的问题，通过理论分析与计算，借助计算机软件，完成了膨化机结构及工艺参数的最优化设计，为机器的改进设计提供了理论指导。 最后，探讨了膨化产品的应用。 通过试验研究得出以下结论: (l)对膨化前后大豆的营养成分分析表明，膨化后的大豆，粗蛋白含量增加了2.69%，灰分增加了7.45%;粗脂肪基本没有减少，粗纤维减少了29.11%，脉酶活性降低了69.03%。可见其营养成分有不同程度地提高，而脉酶等抗营养因子的含量大大降低，利于动物的生长。 (2)膨化后的大豆呈金黄色，多微孔、细粒状，油脂充分暴露表面。借助电子显微镜观察其微观结构，大豆细胞结构被破坏，撕裂变成絮状纤维，细胞间距拉大，油细胞破裂，释放出油脂，易于被动物消化和吸收。 (3)通过单因素试验以及三因素五水平的二次回归正交旋转试验，建立了膨化机度电产量、生产率及膨化压力与其影响因素的数学模型;通过对模型分析，确定了影响度电产量的因素主次顺序为:螺杆转速>物料含水率>膨化温度;影响生产率的因素主次顺序为:螺杆转速>物料含水率>膨化温度;影响膨化压力的因素主次顺序为:物料含水率>膨化温度>螺杆转速。 (4)利用有约束非线性优化理论对大豆膨化工艺参数进行了优化计算。在保证膨化质量的情况下，得到最优工艺参数为:物料含水率19%，螺杆转速17一印m，膨化温度14o.c。 研究结论为指导实际生产，提高膨化大豆的品质以及降低生产成本提供了理论依据。更多还原

【Abstract】 There are abundant soybean resources in China. Soybean’s yield is near upon 15,000,000 tons every year, accounting for the fourth of the world’s one. Soybean has more protein, lipid, amino acid, fatty acid and lecithin than other crops, supplying high quality food for human and high energy, high protein feed for animals. In recent years, along with the development of the stockbreeding in China, demand for protein is increasing continuously. Nevertheless protein resources from animals is limited, which can’t meet the need of the feeding industry, the protein resources must be founded to party replace ones from animals. Soybean protein from the plants has particular advantage. Extruded soybean can replace traditional method of bean cake and lipid, when it is added to feed. The method obtains preferable breed effect.Now, technology of extruding soybean is perfected gradually. But, extruder mostly has complicated structure, large size, high price. It is difficult to manipulate and can’t satisfy the need of individual user and small enterprise. A small reformative extruder is designed for experiment, which has simple structure, low price, and is easy to operate and maintain. The small extruder that is used to process soybean will promote exploitation and utilization of the soybean resources.In order to study the technology of extruding soybean deeply and improve the performance of extrusion experimental equipment, the working principle of extruder is analyzed in this paper. The mechanism of extruding soybean is also preliminarily discussed. On the basis of present equipment, a kind of single-screw extruder is used in this experiment. The main working parts are designed and studied. The factors influence extrusion effect are analyzed synthetically. Soybean moisture content, screw speed, extruding temperature and clearance are different factors. The effect of these factors on extrudingprocession is studied through four single factor experiments in which test indexes are productivity and output per kWh. It provides gist for quadratic regressive orthogonal rotatory experiment.Regression equations for extruding criteria are established though three-factor with five-level quadratic regressive orthogonal rotatory experiments. The effects of soybean moisture content, strew speed, extruding temperature on productivity, output per kWh and extruding pressure are discussed. By establishing a mathematical model, the influences of primary factors which affect the extruding criteria have been analyzed with curve surface function. Finally, the technologic parameters have been optimized by the optimization theory using nonlinear programming method. A group of optimum parameters are confirmed.Aimed at resolving the problems in the experiment, on the basis of analysis and calculation, optimal design of structural and processing parameters of extruder are completed with the help of the software. It provided the theoretic guidance for reformative design of the machine.Finally, the application of extruded production is discussed.From experimental study following conclusions are made.(1) Nutrition composition contrast analysis of soybean and extruded soybean indicate that the crude protein content of extruded soybean increases 2.69%, the ash increases 7.45%, the crude fat doesn’t decrease on the whole; the crude fiber decreases 29.11%, the activity of urease decreases 69.03%. Results show that the nutrition composition of extruded soybean has been changed, which is advantageous to growth of the animals.(2) Extruded soybean is tiny particles form, with many tiny bore, and golden color. The oil is exposed on the surface of extruded soybean. Microstructure of extruded soybean which can be observed with the help the electron microscope, indicates that the cell structure of soybean is destroyed, laniated to floccular fiber, distance of cell is increased, lipocyte is broken and lipid is released. It is easy for animals to digest and imbibe lipid.(3) Through single factor experiment and quadratic regressive orthogona更多还原