挤压膨化工艺参数对玉米淀粉出酒率的影响

合理的原料预处理工艺可以提高玉米淀粉出酒率,该文用单螺杆挤压膨化机对脱胚玉米进行挤压膨化,以模孔直径、套筒温度、物料含水率、螺杆转速和酵母添加量作为因素,以挤压膨化脱胚玉米淀粉出酒率为考察指标,采用5因素5水平(1/2实施)进行二次正交旋转组合试验设计,探讨了挤压膨化工艺参数和酵母添加量对挤压膨化脱胚玉米淀粉出酒率的影响规律,得到了优化的工艺参数:模孔直径为12mm,套筒温度140℃,物料含水率19%,螺杆转速200r?min-1,在酵母添加量为0.4%时,玉米淀粉出酒率可以达到55.81%。     

膨化玉米作啤酒辅料的可行性试验研究

探讨了用不脱胚玉米挤压膨化物作啤酒辅料的可行性。指出：挤压膨化不脱胚玉米的绝干浸出率大于不膨化脱胚玉米的绝干浸出率，接近不膨化大米的绝干浸出率。可以用挤压膨化不脱胚玉米，代替目前传统工艺中不膨化的大米或脱胚玉米，作为酿制啤酒的辅料。同时使脱胚玉米辅料用量减少８％左右，麦芽用量减少１０％左右。     

脱胚玉米啤酒辅料的挤压蒸煮系统参数对其糖化过程的影响

该文通过实验室试验,研究了作啤酒辅料的脱胚玉米挤压蒸煮系统诸参数(模孔孔径、套筒温度、物料含水率、螺杆转速和模板内表面至螺杆末端端面的距离)，对醪液的主要考察指标（麦汁的过滤速度、碘值、浸出物收得率）的影响规律. 研究表明，挤压蒸煮脱胚玉米可以作啤酒辅料，其醪液的淀粉在糖化过程中被降解得彻底，淀粉的利用率较高。     

低温挤压添加酶制剂的玉米粗淀粉的糖化过程试验研究

为了缩短生产玉米糖浆的玉米粗淀粉的糖化时间，改进其糖化过程。通过实验室试验,研究了添加酶制剂的玉米粗淀粉的挤压-液化系统诸参数(套筒温度、玉米粗淀粉含水率、螺杆转速、挤压时耐高温α-淀粉酶添加量、液化时耐高温α-淀粉酶添加量)，对糖液的主要考察指标(糖液的DE值、出品率和过滤速度)的影响规律。研究表明，在本研究的较优系统参数下，糖化12 h糖液的DE值、过滤速度和淀粉出品率分别为95.5%～96.3%、163.2～177.3 L/(m²·s)和94.2%～94.4%。比传统玉米淀粉糖化时间缩短约18 h。     

膨化带胚玉米作啤酒辅料的试验研究

通过试验,研究了带胚玉米挤压膨化系统的诸参数（物料含水率,螺杆转速,套筒温度,模孔孔径）对各考查指标（糊化度、浸出率、脂肪、总还原糖、总酸）的影响规律,及其系统最优参数。结果表明,只要膨化系统诸参数选择合适,不加酶制剂,带胚玉米膨化物对应的麦汁醪液的糖化和过滤也可以顺利进行。     

减少玉米粗淀粉挤出物中抗性淀粉的工艺参数优化

为减少玉米粗淀粉经过挤压蒸煮后,在室温下冷却而产生的抗性淀粉Ⅲ,以降低其对挤出物制备糖化液葡萄糖当量值的影响,需要对挤压参数进行优化选择。该文以玉米粗淀粉为原料,采用五因素五水平二次正交旋转组合试验设计,研究挤压参数对挤出物中抗性淀粉Ⅲ质量分数的影响,得出产生抗性淀粉Ⅲ质量分数最小的挤压条件为：套筒温度60.0℃,原料含水率27.0%,模孔直径11.0 mm,螺杆转速200.0 r/min,轴头间隙10.0 mm,抗性淀粉Ⅲ质量分数可降低到1.48%。     

膨化啤酒辅料酿造啤酒的试验研究

该文利用实验室试验和国产微型啤酒设备,对挤压膨化啤酒辅料与对照不膨化的传统蒸煮糊化啤酒辅料的对应醪液及其定型麦汁进行了试验研究。结果表明:膨化啤酒辅料与不膨化啤酒辅料相比,其麦汁醪液的主要糖化指标及其过滤速率基本相同,麦汁收得率,前者比后者约多8%,发酵时间,前者比后者减少10%;糖化过程的功耗,前者比后者少13%;糖化过程用水量,前者比后者约少用3%。     

玉米挤压淀粉酶法改性制膜的工艺优化

为了提高可降解性玉米淀粉膜的力学性能,并获得玉米挤压淀粉酶法改性制膜的最适工艺参数,该研究以普鲁兰酶为酶制剂来改善玉米挤压淀粉膜,以酶作用温度、pH值、酶添加量、酶解时间及玉米挤压淀粉浓度为试验因子,膜的抗拉强度为响应值,采用中心旋转组合试验设计进行试验。结果表明：5个因素对酶改性挤压淀粉膜抗拉强度的影响大小依次为玉米挤压淀粉浓度＞酶添加量＞酶解时间＞pH值＞酶作用温度;最佳酶解制膜工艺条件为：酶作用温度46.57℃,pH值4.44,酶添加量6.63 u/g,酶解时间9.31 h,玉米挤压淀粉浓度7.00%,在此条件下,膜抗拉强度的预测值为24.3654 MPa,验证试验所得膜抗拉强度为24.2539 MPa,比未改性膜的抗拉强度提高了338.01%。回归方程的预测值和试验值差异不显著,所得回归模型拟合情况良好,达到设计要求。膜的抗拉强度与酶解挤压淀粉中直链淀粉含量之间存在极显著正相关关系,相关系数为0.863。     

甘薯全粉加工及其挤压膨化食品特性的分析研究

探讨制备高品质甘薯全粉的简便方法，及以甘薯全粉为主要原料，通过挤压膨化技术生产甘薯营养食品的可能性，并对挤压膨化过程中营养成分及理化性质的变化进行了研究分析。结果表明，经挤压膨化后，原料中淀粉、蛋白质含量略有下降，总糖含量上升，吸水性，水溶性指数增大，色泽略有加深，并有浓郁的特征香味产生。     

挤压玉米粉制备高麦芽糖浆工艺优化

为缩短超高麦芽糖浆的生产周期、节约能源,该文系统地研究了挤压玉米粉作预处理后生产高麦芽糖浆的工艺,分析了机筒温度、螺杆转速、模孔直径及物料水分与麦芽糖含量、糖浆收率的关系。结果表明:挤压工艺的因素排序为机筒温度>物料含水率>螺杆转速>模孔直径;最佳挤压条件为:59℃、23%、200r/min、6mm,液化10min,糖化8h,经高效液相色谱分析,所制备的糖浆中麦芽糖质量分数为69.19%,糖浆收率可达100.62%,研究结果可为工业化生产麦芽糖提供数据参考。     

挤压法生产淀粉糖浆副产物酶解条件

为实现低值蛋白质资源玉米渣的高质化利用,采用2709碱性蛋白酶,水解挤压法生产淀粉糖浆的副产物玉米渣,确定水解工艺条件.并对水解液中的肽分子质量分布状况及氨基酸组成进行了分析.结果表明,按照本研究工艺路线,采用2709碱性蛋白酶能够较为彻底地水解目标副产物中的蛋白质,水解液中分子质量小于10000 u的水解物大于总量的94.8%,并且绝大部分水解物在二肽、三肽分子质量范围内分布,水解液中含有能够满足人体生理机能需要的多种氨基酸.     

挤压膨化大米做啤酒辅料的试验研究

该文通过实验室试验,研究了做啤酒辅料的大米挤压膨化系统诸参数(模孔孔径、套筒温度、物料含水率、螺杆转速),对醪液的主要考察指标(麦汁醪液的总还原糖、过滤速度)的影响规律,指出挤压膨化大米做啤酒辅料的可行性。     

Fate of Maize DNA During Steeping,Wet-Milling,and Processing

The fate of DNA during steeping, wet-milling, and subsequent processing of maize was examined using a sensitive polymerase chain reaction (PCR-based) detection system. The system used specific amplification of maize DNA sequences by primers generated toward plant nuclear- and chloroplast-encoded genes. The PCR method facilitated analysis of DNA content in food products, which is an important issue in use of genetically modified organisms. In a conventional laboratory wet-milling countercurrent steep system, DNA was detected in maize kernels throughout the process but was not found in steepwater. After kernels were wet-milled, DNA was detected in the starch, germ, coarse fiber, and wet gluten fractions but not in the fine fiber fraction. When dried by heating at 135°C for 2 hr, DNA was degraded to undetectable levels in the wet-milled gluten fraction and hydrated kernels. DNA was not detected in feed pellets, starch, dextrose, sorbitol, or high-fructose maize syrup made from industrial wet-milled samples. Although DNA could be detected in laboratory wet-milled fractions, some degree of degradation occurred after extended exposure to steepwater. Countercurrent steepwater samples from the later stages of the steeping process were able to degrade DNA. The level of DNA degradation appeared to correspond to the presence of sulfur dioxide and may represent a physiochemical rather than an enzyme-mediated process. Our results indicate that some steps in the steeping and wet-milling process can degrade maize genomic and plastid DNA.     

Filtration Characteristics of Maize and Wheat Starch Hydrolysates

Starch hydrolysates were prepared by one- or two-stage hydrolysis with α-amylase. The filtration rate of wheat starch hydrolysates was considerably lower than that of maize starch hydrolysates. Omitting the second conversion step lowered the filtration rates of wheat and maize starch hydrolysates. Increasing the incubation time or the enzyme dosage resulted in an increase of the filtration rate of maize starch hydrolysates due to the increase in the dextrose equivalent. These process variables did not influence the filtration rate of wheat starch hydrolysates. Wheat starch hydrolysates had very poor filtration characteristics: low filtration rates, almost no removal of undesired components, and obstruction of the filter cake. On the contrary, maize starch hydrolysates showed good filtration characteristics: a high filtration rate and removal of the largest part of the undesired components. On storage, wheat starch hydrolysates separated into three layers. The intermediate fraction had a higher filtration rate than the total hydrolysate. Adding small amounts of the upper or lower layers to dextrose solutions decreased the filtration rate to that of a wheat starch hydrolysate. This was due to an increase of the protein and lipid concentration.     

玉米三维重构及可视化系统的设计与实现

重构出植物的三维形态是数字植物研究的基础。介绍了玉米三维重构及可视化系统的整体结构、数学基础及实现过程。系统由器官几何造型模块、生长模型模块、可视化控制模块、数据库和人机交互界面组成。其中，玉米叶片、茎节、雄穗、雌穗和根系的三维形态是由基于器官形态结构主要特征而构建的参数化的几何模型来描述的。模型参数具有较明确的生物学意义，均可由品种特征或生长模型生成；系统运行时，根据玉米品种特征和玉米生长模型生成植株的拓扑结构参数和器官几何模型参数，通过人机交互操作来确定行株距等农艺措施参数，进而结合VC++和openGL在计算机上重构出玉米器官、个体和群体的三维形态，具有较好地真实感。系统界面友好、使用方便，易于交互，为农学研究者提供了新的手段。     

生物转化玉米浆生产生物菌肥的共生发酵特性

玉米深加工是全球第二大宗农产品加工行业,玉米淀粉制备过程中产生大量的副产物,如玉米浆（Maize Steep Liquor, MSL）。玉米浆色深味重、毒素含量高、处理困难,已经成为众多玉米深加工企业发展的桎梏。该研究主要利用玉米浆中丰富的速效氮源和微生物的促生长因子进行微生物菌肥的开发。通过对前期筛选到的3株植物根际促生菌（PGPMs）的共生发酵研究,评估了3种菌在玉米浆中高密度发酵的可行性,并对发酵特性进行了研究。试验结果表明,三种菌通过共生发酵,并在模拟流加工业废料结晶糖母液作为补料时,发酵体系中的总生物量从6.6×109提升到了2.17×1010 CFU/mL,并在52 h氨基酸态氮含量达到最大。同时,采用葡萄糖模拟结晶葡萄糖母液流加补料显著提高了共生体系的总糖以及溶磷的利用率,可溶性磷利用率提高了近50%;此外,添加葡萄糖还能保持发酵体系的pH值稳定,奠定了生产稳定性。该研究为玉米浆的再利用提供了一种解决方法,对低成本生物肥料的开发与生产提供了一种新的思路。     

Properties of low moisture composite materials consisting of oil droplets dispersed in a protein-carbohydrate-glycerol matrix: effect of continuous phase composition

The influence of continuous phase composition on the properties of low moisture (<3% water) composite materials consisting of oil droplets dispersed in a protein-carbohydrate-glycerol matrix was investigated. These composites were produced by blending canola oil (62.3%), whey protein concentrate (1.7%, WPC), and corn syrup and glycerol together (36.0% combined) using a high speed mixer equipped with a whisk. The polyol composition was varied by changing the ratio of corn syrup to glycerol in the system while keeping the total concentration of these two polyol components constant. Some composites were analyzed directly after preparation ("unbaked"), while others were analyzed after heating at 176 degrees C for 10 min to simulate baking of a food product ("baked"). The "lightness" of the composites was greater before baking (higher L value), but the color intensity of the composites was greater after baking (higher b value), which was attributed to Maillard browning reactions. The brownness of the baked composites increased with increasing corn syrup concentration, which was attributed to Maillard browning reactions. Squeezing flow viscometry indicated that the consistency and yield stress of the composites increased with baking, which was attributed to whey protein unfolding and aggregation. These rheological parameters also increased with increasing corn syrup concentration, which was attributed to its influence on the continuous phase rheology and on the interactions between the whey proteins. This study shows that the continuous phase composition and thermal history of low moisture composite materials have a large impact on their final physicochemical properties.     

基于电磁振动的玉米粒群定向整列系统的参数优化与试验

为提高玉米粒群定向整列系统性能及精度,分析电磁振动系统设计参数对定向整列性能的影响.首先,通过分析系统的工作原理,构建了籽粒的滑移模型;其次,开展了系统动力学分析及定向阶段籽粒的受力分析,探讨了籽粒定向整列过程与系统设计参数之间的关系,选取出对系统作业性能有显著影响的参数,得到满足要求的设计参数临界条件;最后,搭建定向整列试验平台,通过三因素二次正交旋转设计试验,进一步优化设计参数,建立因素与试验指标(定向成功率、整列成功率)的回归方程.经优化计算得出:最佳设计参数范围为振动方向角32°~35°、振幅为0.1~0.15 mm、振动频率为51.5~52 Hz,相对应的试验指标定向成功率范围为63.8%~67.4%,整列成功率范围为95.8%~96.3%,其中最优参数组合为:振动方向角34.42°、振幅为0.14 mm、振动频率51.77 Hz;将系统置于最优参数组合进行验证试验,同时借助高速摄像系统对籽粒定向整列过程实时记录和分析,在无机械机构辅助的情况下,平均定向成功率为66.2%,整列成功率为97.4%.该研究可为玉米籽粒定向种植、定向育苗等相关装备的研制提供参考.