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排序方式: 共有128条查询结果,搜索用时 46 毫秒
1.
玉米胚挤压膨化系统参数优化试验 总被引:6,自引:2,他引:6
研究了用于浸油的玉米胚挤压膨化系统参数(模孔孔径、套筒温度、物料含水率、螺杆转速)对各考察指标(粕的残油率、剪切强度及糊底程度)的影响规律.并对其参数进行了优选。同时对最佳参数的膨化玉米胚与传统浸油的轧胚玉米胚、原始玉米胚的显微结构进行对比分析。研究表明:玉米胚挤压膨化系统参数选择合适,浸出时玉米胚不糊筛底,残油率小于0.5%。 相似文献
2.
法兰类锻件挤镦过程的有限元分析 总被引:3,自引:0,他引:3
采用有限元法对法兰类锻件的挤镦成形过程进行了有限元分析计算,与试验结果对比表明,无论是等效应变ε分布曲线,还是压力载荷位移曲线都趋于一致,从而为应用塑性有限元法指导法兰类锻件的工艺设计提供了依据。 相似文献
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4.
Rashmi Kumari Hirokazu Ito Masahiro Takatani Miho Uchiyama Tadashi Okamoto 《Journal of Wood Science》2007,53(6):470-480
Although wood/cellulose-plastic composites (WPC) of low wood/cellulose content have been more accepted worldwide and are promoted
as low-maintenance, high-durability building products, composites containing high wood/cellulose content are not yet developed
on an industrial scale. In this study, flow properties, mechanical properties, and water absorption properties of the compounds
of cellulose microfiber/polypropylene (PP) and maleic anhydride-grafted polypropylene (MAPP) were investigated to understand
effects of the high cellulose content and the dimensions of the cellulose microfiber. The molding processes studied included
compression, injection, and extrusion. It was found that fluidity is not only dependent on resin content but also on the dimension
of the filler; fluidity of the compound declined with increased fiber length with the same resin content. Dispersion of the
composite was monitored by charge-coupled device (CCD) microscope. Increasing the plastic content in the cellulose-plastic
formulation improved the strength of mold in addition to the bond development between resin and filler, and the tangle of
fibers. The processing mode affected the physicomechanical properties of the cellulosic plastic. Compression-molded samples
exhibited the lowest modulus of rupture (MOR) and modulus of elasticity (MOE) and the highest water absorption, while samples
that were injection-molded exhibited the highest MOR (70 MPa) and MOE (7 GPa) and low water absorption (2%). 相似文献
5.
Elena de la Peña Frank A. Manthey Bhavesh K. Patel Osvaldo H. Campanella 《Journal of Cereal Science》2014
A study was conducted to investigate the effect of dough formulation and hydration level on the rheological properties of pasta dough during pasta extrusion. Semolina 100%, whole wheat 100%, and the following mixtures semolina-whole wheat (49:51), semolina-flaxseed flour (90:10), whole wheat-flaxseed flour (90:10), and semolina-whole wheat-flaxseed flour (39:51:10) were the formulations used for the experiments. Dough was hydrated at 30, 32, and 34% moisture content. Pasta was extruded with a capillary and a semi-commercial pasta extruder to determine the apparent viscosity of the dough during extrusion conditions and its relationship to the behavior of the dough during pasta processing. Results showed that non-traditional pasta dough behaved like a shear thinning fluid that can be described by the Power Law model. Increased hydration levels and/or presence of flaxseed flour on the dough formulation decreased the apparent viscosity of the dough, which correlated with extrusion pressure, mechanical energy, and specific mechanical energy that were required to extrude the dough in the pasta extruder. The strong correlations found between the apparent viscosity of the dough and the pasta extrusion parameters indicates the possibility of using a capillary rheometer to determine the appropriate hydration level of ingredient formulations before extruding with a pasta press. 相似文献
6.
The rheological changes in rice noodles by the substitution of corn bran and the effect of temperature on the xanthophyll content (lutein and zeaxanthin) of the corn bran-rice flour noodles were evaluated. The use of corn bran increased the water holding capacity of rice flour at room temperature while the opposite results were observed after heating. The pasting parameters of rice flour-corn bran mixture were reduced with increasing levels of corn bran and the mixture paste exhibited more dominant liquid-like behavior. The noodles containing corn bran exhibited lower expansion ratio and softer textural properties. The levels of lutein and zeaxanthin in raw corn bran were 336.9 and 123.1 μg/100 g, respectively and were significantly reduced (P < 0.05) by heating. While lutein and zeaxanthin were not detected in the control noodles without corn bran, their levels in corn bran-incorporated noodles ranged from 56.2 to 137.3 μg/100 g and from 37.9 to 61.9 μg/100 g, respectively and were significantly reduced by 37.7–45.4% (P < 0.05) after cooking. Thus, the heat-labile characteristics of two xanthophylls were clearly observed. This study provides useful information on the processing performance and xanthophyll content of corn bran, possibly extending its use in a wider variety of foods. 相似文献
7.
Jose Martin Ramos Diaz Satu Kirjoranta Seppo Tenitz Paavo A. Penttilä Ritva Serimaa Anna-Maija Lampi Kirsi Jouppila 《Journal of Cereal Science》2013
Amaranth (Amaranthus caudatus), quinoa (Chenopodium quinoa) and kañiwa (Chenopodium pallidicaule) are pseudocereals regarded as good gluten-free sources of protein and fiber. A co-rotating twin screw extruder was used to obtain corn-based extrudates containing amaranth/quinoa/kañiwa (20% of solids). Box–Behnken experimental design with three independent variables was used: water content of mass (WCM, 15–19%), screw speed (SS, 200–500 rpm) and temperature of the die (TEM, 150–170 °C). Milled and whole samples were stored in open headspace vials at 11 and 76% relative humidity (RH) for a week before being sealed and stored for 9 weeks in the dark. Hexanal content was determined by using headspace gas chromatography. Extrudates containing amaranth presented the highest sectional expansion index (SEI) (p < 0.01) while pure corn extrudates (control) presented the lowest SEI and greatest hardness (p < 0.01). SEI increased with increasing SS and decreasing WCM. In storage, whole extrudates exposed to 76% RH presented the lowest formation of hexanal. This study proved that it was possible to increase SEI by adding amaranth, quinoa and kañiwa to pure corn flour. The evaluation of lipid oxidation suggested a remarkable stability of whole extrudates after exposure to high RH. 相似文献
8.
E. Solanas C. Castrillo M. Fondevila Q.O. Ruiz Narvez J.A Guada 《Livestock Science》2008,117(2-3):203-214
The effect of extruding the cereal and/or the protein supplement of a compound feed on its nutritive value and on the performance of intensively reared male calves was studied. The compound feed was formulated with 0.65 of a cereal blend (60:40 maize:barley), 0.25 of a protein blend (1/3:1/3:1/3 raw soybeans:peas:lupins), and 0.08 of urea to contain 0.17 of crude protein. It was tested without extruding (NE) and with the cereal blend (CE), the protein blend (PE) or both (CPE) extruded. Another non-extruded compound feed with mainly soybean meal as the protein supplement (NE-SBM) also was studied. The five experimental compound feeds together with barley straw were offered ad libitum to 50 male Friesian calves (112 kg initial live weight) for 13 weeks, recording individual feed intake and live weight gain. Crude protein (CP) solubility and in vitro and in situ CP degradation of experimental compounds, and in vitro gas production kinetics, in vivo digestibility and urinary allantoin excretion of diets were determined. Cereal extrusion promoted a greater gas production at all incubation times (p < 0.001), associated to the increase in starch gelatinisation. PE and NE-SBM compounds showed lower in vitro (p < 0.01) and in situ (p < 0.001) CP degradability than the other feeds. Ingredient extrusion did not affect apparent DM, OM and CP digestibilities, but diet CPE showed a lower NDF digestibility (p < 0.05) than the others (0.293 vs. 0.420, 0.387, 0.390 and 0.407 with CPE vs. NE, CE, PE and NE-SBM, respectively). The apparent EE digestibility increased (p = 0.053) with the inclusion of extruded ingredients, (0.799, 0.749 and 0.794 vs. 0.719 and 0.702 with CE, PE and CPE vs. NE and NE-SBM, respectively). Daily allantoin excretion was lower (p < 0.01) in calves receiving the CPE diet than in those receiving the NE, PE and NE-SBM diets. Treatments did not affect the average daily gains (1.61 ± 0.022 kg d− 1), however calves on the CPE diet showed a lower (p < 0.01) concentrate and total conversion ratios than those fed NE, PE and NE-SBM (2.60 vs. 2.79, 2.85 and 2.98 kg concentrate DM kg− 1 daily gain and 2.93 vs. 3.09, 3.13 and 3.26 kg total DM kg− 1 daily gain, respectively). The CE diet resulted in numerically higher (p > 0.05) concentrate and total DM conversion ratios (2.72 and 3.02) than CPE and lower (p < 0.05) than NE-SBM. Improvement in feed conversion ratio after extrusion would be related to a better starch utilisation and not to changes in microbial or dietary protein flow to the duodenum, although a better utilisation of fat energy cannot be disregarded. 相似文献
9.
[目的]研究花生挤压膨化制油工艺,简化制油工序,降低粕残油率。[方法]通过高含油料单螺杆剖分式挤压机对花生进行浸油的前处理,根据量纲分析理论进行试验设计和函数组成,以物料含水率、套筒温度、主轴转速、模孔直径、模孔长度、喂料速度6因素设计试验,找出花生挤压膨化工艺参数对粕残油率的影响规律。[结果]通过该试验建立的方法得到的关于粕残油率的经验公式可以对粕残油率进行精确预测,经验公式在现有试验条件下可反映花生残油率与挤压膨化试验参数间的关系。[结论]通过试验建立粕残油率和试验参数的经验公式,且经验公式对粕残油率能进行较好地预测。 相似文献
10.