【作者】 马稚昱；

【导师】 陈立；

【作者基本信息】 东北农业大学 ， 农业生物环境与能源工程， 2003， 硕士

【摘要】 挤压膨化加工具有改善血粉品质、提高血粉消化率、简化生产工艺、保护环境等优点。研究和探讨挤压膨化工艺参数对血粉质构变化的规律，是挤压膨化技术在血粉加工中得以在实际生产应用的理论基础，它将对我国畜禽屠宰废弃血液资源的开发利用产生积极的影响。 本研究利用中国农业机械化研究所畜禽机械研究所生产的单螺旋式P400G自热式干法膨化机，研究和探讨挤压膨化加工工艺参数对膨化血粉的膨化指数、胃蛋白酶消化率及设备的生产能力和耗能的影响规律，分析膨化后血粉主要营养成分及微观结构的变化，寻找膨化加工工艺参数的最佳组合，为实际生产加工提供可借鉴的理论依据。 试验结果表明： 1．变性温度T_d是血粉蛋白质变性的决定因素。我们采用差示扫描量热法对血粉蛋白质变性温度进行研究得到：在DSC测试仪的升温速率为5℃／min时，含水率为16％的自然凉晒血粉的蛋白质变性温度为76.9℃。 2：在单螺旋干法自热式膨化机上，通过单因素试验分析，得到挤压膨化加工工艺参数——物料含水率、出料模孔直径及螺杆转速对膨化血粉品质的影响规律：随着含水率的增加，膨化血粉的胃蛋白酶消化率增加，达到最大值后开始下降；螺杆转速与膨化血粉胃蛋白酶消化率呈负相关性；随着模孔直径的增加，膨化血粉胃蛋白酶消化率增加，当模孔直径等于13mm达到最大值，后呈下降趋势。 3：本研究采用三因素五水平进行二次正交旋转组合实验设计，研究挤压膨化系统参数——物料含水率、出料模孔直径及螺杆转速对膨化血粉品质——膨化指数和为胃蛋白酶消化率及设备生产率和吨电耗的影响，建立了各评价指标与膨化参数的数学模型，并结合模糊综合评判法与频数分析法对多目标进行优化求解，建立综合评判方程，从理论上得到：同等重视4个评价指标时，最优的挤压膨化系统参数：含水率23±1.02％，模孔直径14.5±0.65mm，螺杆转速234.5±6.5 r／min；而将胃蛋白酶消化率和吨电耗作为主要评价指标时，最优的挤压膨化系统参数：含水率22.57±1.18％，模孔直径15±0.5mm，螺杆转速207.1±7.5 r／min。 4：通过采用扫描电镜技术对膨化血粉与普通血粉颗粒的微观结构进行观察，结果表明与普通血粉相比，膨化血粉的颗粒表面酥松、分层、形状无规则、有光泽，颗粒是由无数个大大小小、相互链接的空洞组成，这种结构增大了消化酶和血粉颗粒的接触面积，提高了血粉的消化率，并能防止混合饲料中其他微量元素在运输过程中的损失。 5：与普通血粉相比，本实验所生产的膨化血粉胃蛋白酶消化率提高了3.3个百分点，说明挤压膨化加工技术可以改进血粉的品质，提高其营养成分吸收；膨化血粉的含水率较低，有利于血粉的贮藏。更多还原

【Abstract】 Animal blood is rich in protein, containing up to 80%. There are such common methods to process blood as drum drying, spray drying and fermentation, which may have the disadvantages of low digestibility, high cost for processing and environmental pollution. Many efforts are made to have good use of blood into protein ingredients for feed in the world. The extrusion cooking (E-C), treating the powder blood with high temperature and short time (HTST), increases the digestibility of the blood. Studying the effects of E-C parameters on blood meal is the theory base of E-C practical production. It will have positive effects on exploitation of trash blood resource.The research studied on the effect of E-C parameters on quality of blood meal and the extruder performance characteristics, analyzed the change of main nutritional ingredient and microstructure of expanding blood meal, and gave the technologic parameters for practical production.The research result show that:l.The research studied the variety regularity of protein denaturation temperature of blood meal by Differential Scanning Calorimetry (DSC). The study shows that denaturation temperature is crucial factor. When the DSC’ s calefactive speed is 5 degrees centigrade per minute, protein denaturation temperature is 76.9 degrees centigrade.2. We summarized the influence regularity of the extrusion parameters on the quality of expanding blood meal by single factor experimentation. The regularity shows that:Fixed other factors, the pepsin digestibility of expending blood meal firstly increases with the increase of moisture content, but when moisture content increase to maximum, the pepsin digestibility begins to descend.Fixed other factors, the pepsin digestibility descends with the increaseof screw speed.Fixed other factors, the pepsin digestibility increases with the increase of die diameter, but when die diameter increases to 13 millimeter, the pepsin digestibility begins to descend.3. The research studied the influence regularity of extrusion system parameters on quality of expanding blood meal and the extruder performance characterstics by the method of quadratic orthogonal rotation combinationdesign test of three factors and five levels, and evaluated the optimum solution of multi-objectives nonlinear programming problems by combining fuzzy integration order with frequency analysis. The study shows that:When the importance of four objectives is the same level, the optimized system parameters of extrusion are follows: the moisture of fed blood meal 23 +1.02%, the die diameter 14. 5 + 0. 65mm, the screw rotate speed 234.5+6.5 r/min-.When the pepsin digestibility and the electricity consumed of unit product are the main factors, the optimized system parameters of extrusion are follows: the moisture of fed blood meal 22. 57?. 18%, the die diameter 15?. 5mm, the screw rotate speed 207.1 + 7.5 r/min.4. The comparison of microstructure between expanding blood meal and common blood meal indicate that: The granule surface of expanding blood meal is loose, delaminatiorK ruleless and lustrous. The granule is built of countless holes that are conterminous each other. The structure is very crisp and insubstantial. One hand the structure increase the contact area of digestive enzyme and granule, on the other hand else nourishment ingredients fill the holt of granule, thereby avoiding the loss of these nourishment ingredients on transportation.5. The comparison of the expanding blood meal produced by our experimentation with common blood meal show that: the pepsin digestibility of the former increases 3.3 centesimal points. This may elucidate that the extrusion technology can improve the quality of blood meal and enhance the digestibility of nourishment ingredients. On the other hand the moisture content of expanding blood meal descend, thereby making for store.Graduate student: Ma Zhiyu Major: Environment and Energy Sources Engineering of Agricultural Biology Supervisor: Associate prof. chen li更多还原