基于CFX的豆粕单螺杆挤出机的三维流场分析

运用CFX方法对具有转动螺纹机筒的单螺杆挤出机的流道进行流场分析,研究分析豆粕在其流道中的运动情况,包括速度矢量图、速度流线图、宏观压力图及挤出量,与具有普通机筒的单螺杆挤出机进行对比分析。结果表明:由于机筒具有反向螺纹及反向转动功能,使流场建压能力增强,挤出性能大幅度提高,速度流线产生涡运动,豆粕充分混合。研究结果可为单螺杆挤出机加工提供理论参考。     

开槽捏合块混炼元件在豆粕挤压加工中的应用及其流场研究

为了提高豆粕加工双螺杆挤出机的混合性能,采用ANSYS-CFX对带有开槽捏合块混炼元件的双螺杆挤出机流道进行三维流场分析,比较豆粨在开槽捏合块及普通捏合块挤出过程中的运动规律。包含速度场、压力场、加权平均剪切速率,以及挤出机流场的对比分析。结果表明:开槽捏合块元件相比于常规捏合块能够显著增强对豆粨的剪切速率,使剪切速率提高1.4倍,能够使轴向建压能力增强,在凹槽处形成背压区,增加豆粨在开槽处的运动时间,提高双螺杆挤出机的分散混合性能。     

大豆异黄酮提取新工艺的研究

目前工业是以乙醇为溶剂进行提取豆粕中的大豆异黄酮,由于豆粕中大豆异黄酮含量只有几千分之一,其含量较低。而在大豆胚中大豆异黄酮的含量较高,以大豆胚为原料,用乙醇和正己烷为溶剂混合萃取,其目的是为了提高异黄酮提取率,为大豆异黄酮的提取寻找新的工艺路线并对其工业生产的可行性进行进分析。     

二元复合菌固态发酵豆粕制备大豆肽的研究

以普通饲料豆粕为原料,选用枯草芽孢杆菌、啤酒酵母和黑曲霉作为发酵菌种,以发酵产物中的可溶性蛋白(包括游离氨基酸和小肽)为测定指标,对影响固态发酵豆粕制备大豆肽的主要因素,包括不同的二元组合菌种、菌种比例、菌种接种量、发酵时间、基质水分含量、发酵温度进行了单因素研究;并运用响应面法对最优组合菌种固态发酵大豆肽的条件进行了...     

纳豆菌发酵对豆粕脲酶活性的影响

微生物发酵可一定程度降低豆粕抗营养因子活性，提高豆粕作为蛋白源的利用率。采用2株纳豆菌发酵研究豆粕中脲酶的失活情况。首先测定了其生长曲线，用以指导其发酵条件的优化研究。研究了水／豆粕比例、培养温度、pH、接种量等发酵参数对脲酶活性的影响，结果表明：降低脲酶活性的最优发酵条件为：彬豆粕比例为5：1，pH4．5、温度30℃、接种量5％、种龄为8h，发酵60h，豆粕脲酶活性降低93％。     

陆地棉焦磷酸酶基因GhVP的启动子序列分析

为了筛选棉花耐盐转基因育种所需的诱导型候选启动子，本研究根据陆地棉焦磷酸酶基因GhVP的cDNA序列和陆地棉基因组序列，获得陆地棉焦磷酸酶基因GhVP启动子序列，并对其进行生物信息学分析。结果表明，该启动子具有多个基本元件TATA-box和CAAT-box，并含有多种逆境胁迫诱导相关的响应元件，含有丰富的光响应元件以及其他多种顺式作用元件。推测GhVP基因的转录同时受光、高温、干旱、创伤、脱落酸诱导，受生物钟控制的顺式元件调控，参与棉花的生长发育。     

豆粕生物肽的生产工艺研究

通过菌种筛选、摇瓶发酵条件优化,系统地研究了微生物发酵生产豆粕生物肽的工艺。结果表明:枯草芽胞杆菌为最佳菌株,其豆粕生物肽最佳生产工艺条件为:种子培养时间16 h,豆粕粒度40目,初始pH6.8,葡萄糖2%,豆粕11%,接种量6%,发酵时间48 h;在此工艺条件下蛋白质降解为多肽的得率为41.18%。     

基于响应面法的豆粕挤压系统参数优化

为了考察挤压膨化生产大豆组织蛋白过程中相关参数对系统参数的影响,以豆粕为原料,利用响应面模型,以豆粕含水率、膨化机螺杆转速和机筒温度为输入变量,以扭矩为响应变量,探索豆粕挤压膨化系统的相关参数对扭矩影响规律和挤压膨化系统最佳参数。结果表明:豆粕含水率、膨化机螺杆转速和机筒温度对扭矩具有显著的影响;膨化机转速是影响扭矩的主要因素。采用优化方法对试验参数进行了优化计算,当豆粕含水率为17.2%、膨化机转速为202.5 r.min-1、机筒温度为110℃时,膨化机工作性能指标达到最优。     

2种输胶泵的改造方法

分析了离心泵和单螺杆泵在乳胶生产中的运行缺点,并对这2种泵设备进行了改造,在实际生产中起到了方便、实用和高效的效果。     

应用普通PCR与实时荧光标记PCR技术检测玉米子粒中转基因成分的比较

对比普通PCR法和实时荧光标记PCR法检测玉米子粒中转基因成分的检测效率,外源基因选取调控元件Ca MV35S启动子、NOS终止子、BAR、Cry IA(b)基因。普通PCR法在进行PCR扩增反应、电泳检测和凝胶成像后,进行结果判定;实时荧光标记PCR法的结果数据由Ct值判定,在一定范围内符合要求的数据即判定有效。通过两种方法比较,与普通PCR方法相比,实时荧光标记PCR法具有检测时间短、检测效率高、对环境造成的污染小等特点。     

醇法连续提取大豆浓缩蛋白及其副产物综合利用的生产实践

以脱脂低温大豆粕为原料,采用乙醇复式萃取器,双螺杆高湿挤压机挤压脱溶的连续生产工艺制取大豆浓缩蛋白.确定了最佳生产工艺条件.在制取大豆浓缩蛋白的基础上,在乙醇提取液的浓缩物大豆糖蜜中,提取分离具有特殊生理活性的大豆异黄酮、皂甙和低聚糖,生产出具有较高附加值的产品.     

Aqueous extraction of residual oil from sunflower press cake using a twin-screw extruder: Feasibility study

The objective of this study was to evaluate the feasibility of an aqueous process to extract the residual oil from sunflower press cakes using a co-rotating twin-screw extruder. Two different configurations were tested: the expression from whole seeds followed by the aqueous extraction, in two successive apparatus or in the same one. For the aqueous extraction stage, the oil yield depended on the operating conditions including screw rotation speed, screw profile, and inlet flow rates of press cakes and water. Liquid/solid separation required the addition of a lignocellulosic residue (wheat straw), upstream from the filtration zone. However, even with maximum fiber inlet flow (around 20% of the inlet flow rate of the solid matters for the highest amount of wheat straw), drying of the cake meal did not improve. The lixiviation of the material was also incomplete. Oil yield was better when the expression and the aqueous extraction were conducted in the same extruder. For all the trials carried out using such a configuration, the corresponding cake meal contained less than 10% residual oil, and the total oil yield was 78% in the best operating conditions. Nevertheless, the contribution of the aqueous extraction stage was extremely limited, less than 5% in the best trial, partly due to a ratio of the water to the press cake too low. For the aqueous extraction stage, the oil was extracted in the form of an oil-in-water emulsion whose stability was minimized because of its low proteins content due to their thermo-mechanical denaturation during the expression stage.     

Effects of extrusion cooking on functional properties of mixtures of full-fat soy and sweet potato

Full-fat soy and sweet potato were extruded at 0:100, 25:75, 50:50, 75:25 and 100:0 ratios in an Insta-Pro 600 single screw extruder operated at 180, 200, 220 rpm respectively. Functional properties: bulk density, expansion ratio, water absorption and solubility indices and trypsin inhibitor were assayed. Results showed that addition of soybeans to sweet potatoes considerably increased the protein, fat, ash and trypsin inhibitor levels of the raw material mixtures. It also led to decreases in viscosities of raw mixtures, with corresponding increases in pasting temperatures. Addition of soybean significantly (p<0.05) affected expansion ratio, water absorption and solubility indices and trypsin inhibitor but not bulk density. Variation in screw rotation speed (rpm) significantly (p<0.05) affected only water solubility index at increasing speed. Extrudates generally received severe heat treatment, rendering them applicable only in soup bases, flour mixes and breakfast foods.     

响应面优化豆粕生物肽的生产工艺研究

以高温豆粕为原料,枯草芽孢杆菌为试验菌株,在单因素试验基础上,以发酵液a-N含量为响应值,对摇瓶发酵制备大豆肽工艺条件进行响应面优化.确定最佳工艺条件为:豆粕粒度40目,初始pH 6.8,种子培养时间16.25 h,碳源用量1.75％,豆粕用量10.75％,接种量6.25％,发酵时间48 h.在此条件下,发酵液α-N含...     

含水率对大豆秸秆流动力学性能的影响

通过直剪切试验,测定分析细碎化处理后大豆秸秆的内摩擦角、粘聚力和流动函数值,研究其流动力学特性,为大豆秸秆纤维制取机螺杆的优化设计提供理论依据.以细碎化处理后大豆秸秆含水率为试验因素,采用单因素对比试验方法,得出了细碎化处理后大豆秸秆的内摩擦、粘聚力和流动函数值随含水率变化的显著性程度及其变化趋势.结果表明:含水率对内...     

全球大豆贸易格局变化对我国大豆产业的影响及对策选择

2019年中央一号文件提出"实施重要农产品保障战略""科学确定国内重要农产品保障水平""主动扩大国内紧缺农产品进口,拓展多元化进口渠道",时隔17年再次提出"实施大豆振兴计划"并首次写入中央一号文件。大豆是中国统筹利用国内外两个市场、两种资源最具代表性的产品。中美贸易摩擦给国内外大豆市场带来了深远影响,世界大豆贸易流向出现显著变化,对中国的大豆进口多元化布局、大豆生产布局和国内农业供给侧结构调整带来较大冲击。因此,如何应对全球大豆贸易格局变化对我国大豆产业所造成的风险尤为重要。首先,加强与"一带一路"沿线国家合作;其次,认清我国大豆产业链发展短板,推进农业供给侧结构性改革;再次,支持大豆主产区转型升级发挥区域优势,提高国产大豆自给率;最后,提高饲用豆粕有效利用率,大力增强饲料技术创新,通过进口杂粕、菜粕等代替豆粕,降低大豆进口依赖。     

大豆热脱皮工艺生产实践与效果分析

在大豆浸出制油过程中,通过增加脱皮工艺,可得到高蛋白去皮豆粕。其目的是,提高豆粕的蛋白质含量,增加浸出设备的处理量,减少生产过程的能量消耗,改善油品质量。工大集团中大植物蛋白开发股份有限公司应用热脱皮工艺生产高温豆粕,并根据不同的需要生产不同蛋白含量的等级豆粕,此种工艺可明显增加企业经济效益。     

A comprehensive 3D analysis of polymer flow through a conical spiral extrusion die

Several restrictions which are related to extruder machinery and nature of process material exist in the design of plastic extrusion dies. To this respect, it is very important to consider design criteria and limitations in order to operate extrusion dies at desired production rate and temperature. In the current study, flow field characteristics through a conical spiral mandrel die are analysed in detail by 3D Computational Fluid Dynamics (CFD) simulations. The effects of operating conditions such as production rate and temperature on pressure drop through the spiral mandrel die and the occurence of melt fracture are investigated. The temperature dependent viscosity versus shear rate data for grade QB79P (CarmelTech) polypropylene (PP) melt under study are measured by use of rotational and capillary rheometers. Stress terms in the momentum equations are modeled by Generalized Newtonian Fluid (GNF) Model. For this, Bird-Carreau Model is employed as the viscosity model for the polymer melt. 3D CFD analyses provide comprehensive data and understanding with regard to flow behaviour through complex extrusion dies.