高组织化大豆拉丝蛋白的挤压工艺参数研究

文章研究了高组织化大豆拉丝蛋白生产过程中大豆蛋白与小麦蛋白的配比关系以及挤压温度、螺杆转速和物料水分含量对高组织化拉丝蛋白特性的影响,确定了拉丝蛋白的最佳挤压参数和所需的物料配比。研究表明:挤压温度与物料水分对高组织化拉丝蛋白色泽、质构和组织化度均有显著影响,螺杆转速对其品质的影响整体不显著,影响拉丝蛋白感官性质的挤压参数主次因素依次为物料水分>挤压温度>螺杆转速。制备高组织化拉丝蛋白的最优挤压工艺参数为挤压温度165℃、水分含量55%、螺杆转速28 Hz。同时,随着挤压原料中小麦蛋白含量的增加,高组织化拉丝蛋白纤维结构逐渐形成,并掩盖了大豆蛋白的豆腥味赋予其谷物香味,改善了最终产品的口感、颜色和质地,提高了挤压产品的整体接受度。

以牛肉为基准高水分组织化植物蛋白的工艺优化

为探究高水分组织化植物蛋白(HMTVP)模拟块状熟牛肉的最佳工艺,以大豆分离蛋白、小麦淀粉、谷朊粉、豆粕为原料进行高水分挤压,并基于熟牛肉的应变率和质构特性对HMTVP原料配方和双螺杆挤压工艺参数进行单因素分析及响应面优化。结果表明:大豆分离蛋白能提升HMTVP的硬度和咀嚼度,淀粉和进水量会降低HMTVP的硬度,喂料量在一定范围能提升HMTVP硬度;在大豆分离蛋白含量32.79%、小麦淀粉含量15.83%、谷朊粉含量24.43%、豆粕含量42.78%,进水量3.4 L/h,喂料量2.8 kg/h条件下,HMTVP的硬度为12.75 kg、咀嚼度为8.27 kg、应变率为0.92×10^(-4),实际水分含量为58.62%,与五级熟度牛肉的质构特性相近;并且在此挤压配方及工艺下制备的HMTVP感官评分较高。HMTVP具有模拟动物肉的巨大潜力,为其在食品工业中的广泛应用提供了有力的参考依据。

高水分组织化大豆蛋白干燥与复水特性研究

高水分组织化大豆蛋白是一种应用湿法挤压技术生产的植物蛋白仿肉制品。本文以高水分组织化大豆蛋白为试验材料,研究了其干燥特性与复水特性。结果表明:(1)60℃为样品最佳干燥温度,粒状样品在该温度下干燥50min,带状样品干燥120min均能使水分降到5％以下。(2)样品的干燥温度和复水温度对样品的复水特性均有显著影响(α<0．01)。当复水温度为30℃、60℃、90℃时,最大复水率分别为155％、 211％和309％。通过质构分析发现,烘干型样品在30℃复水55—60min,60℃复水30—35min,90℃复水15— 20min后均可达到对照样品(鲜样)的质地。结合感观分析,建议食用前将烘干型高水分组织化大豆蛋白在 30℃水中复水55—60min或在60℃水中复水30—35min。

高水分组织化花生蛋白产品干燥和复水特性研究

采用双螺杆挤压机研制的高水分组织化花生蛋白产品中(HM-TPP)蛋白质含量高,具有与动物肌肉类似的纤维状结构和口感,可作为食品原料和配料。文中主要分析了高水分组织化花生蛋白产品的干燥和复水特性。干燥试验结果表明:随干燥温度的增加制品中水分含量达到10%以下所需干燥时间明显缩短,在40、50和60℃下,分别需干燥4.5、7和13 h。其中,60℃下的干燥速率明显高于50℃和40℃下的干燥速率。干制HM- TPP产品的复水试验结果显示:在复水前期(1 h),水温40℃和60℃时的复水速率明显高于20℃的,但40℃和60℃的复水速率无明显区别。复水2.5～3.5 h后,复水产品中水分含量基本达到饱和状态。所得复水产品质地柔韧、表面光滑,富有弹性,基本可以恢复到新鲜产品的品质特性。

高水分植物蛋白组织化简介

在我国,高水分植物植物蛋白组织化是食品领域界一项新型食品处理加工技术,国内市场前景广阔。本文简单介绍高水分植物蛋白组织化的定义、研究难点、原料领域和高水分植物蛋白组织化技术及相关产品的应用。

复配蛋白对小麦蛋白挤压组织化产品特性的影响

以小麦蛋白为主料,复配大豆分离蛋白、花生蛋白、豌豆蛋白等植物蛋白,采用单纯形格子点集混料实验设计进行挤压实验,并用因子分析法对产品进行综合评价,研究原料复配比例对小麦高水分挤压组织化蛋白品质特性的影响。得到原料配比与综合评分的回归模型,以及原料最优配比:W_(小麦蛋白)∶W_(花生蛋白)∶W_(豌豆蛋白)=0.655∶0.135∶0.21。

籼米粉添加量对高水分组织化植物蛋白品质的影响规律研究

为增加籼米碎米利用率,促进碎米的高值化利用,改善高水分挤压组织化植物蛋白的品质,控制谷朊粉、大豆分离蛋白和豆粕的添加质量不变,采用不同质量百分含量(24.67%、20.67%、16.67%、12.67%、8.67%)的籼米碎米粉完全替代小麦淀粉,制作高水分组织化植物蛋白。研究发现,随着籼米碎米粉添加量的增加,组织蛋白产品的明度L^(*)值从74.76提升至79.45,持油性从0.75 g/g提升至0.80 g/g。相较于对照组,添加籼米粉的组织化蛋白的组织化度、硬度、回复性、内聚性、黏着性、咀嚼性等均有显著提升,感官品质也得到了改善。当籼米粉添加量为12.67%时,产品的感官评价总分达到最高,质构、组织化度与多汁性之间达到了平衡,综合品质最优。

添加鱼粉对高湿挤压技术生产三疣梭子蟹配合饲料的性状影响

以大豆分离蛋白中添加不同含量鱼粉为原料,利用高湿挤压技术生产三疣梭子蟹配合饲料。实验设置了8个处理组,鱼粉含量分别设计为：10%、20%、30%、40%、50%、60%、70%、80%。每个处理组混合配料1 kg。实验结果显示,随着鱼粉添加量的增加,产品的组织化度、弹性、聚结性逐渐下降,硬度增加。鱼粉的添加量上限为80%,在50%时开始发生喷爆,60%~80%的混合物挤出后产品组织化程度低,易碎。

以猪肉为基准高水分组织化植物蛋白的工艺优化

组织化植物蛋白作为肉类替代品,存在质构单一、保水性不佳等亟待解决的问题,制约了组织化植物蛋白产品的商业化。其中,质构的仿真度是最大的壁垒,该论文研究了仿猪肉高水分组织化植物蛋白的生产工艺,以猪肉的应变各向异性为基准,对高水分组织化植物蛋白进行工艺优化。结果表明:影响高水分组织化植物蛋白应变各向异性大小的顺序为:加油量>淀粉含量>谷朊粉含量,优化的最佳原料配比为谷朊粉含量10.00%、加油量3.54%,淀粉含量20.45%。经过工艺优化,得到高水分组织化植物蛋白的品质指标为:硬度(12.94±0.17)kg、组织化度1.92±0.03、应变各向异性1.57,与猪肉的质地基本一致。

Microstructural evolution and mechanical properties of duplex-phase Ti6242 alloy treated by laser shock peening

The effects of laser shock peening(LSP)on the microstructural evolution and mechanical properties of the Ti6242 alloy,including the residual stress,surface roughness,Vickers microhardness,tensile mechanical response,and high-cycle fatigue properties,were studied.The results showed that the LSP induced residual compressive stresses on the surface and near surface of the material.The maximum surface residual compressive stress was−661 MPa,and the compressive-stress-affected depth was greater than 1000μm.The roughness and Vickers micro-hardness increased with the number of shocks,and the maximum hardness-affected depth was about 700μm after three LSP treatments.LSP enhanced the fraction of low-angle grain boundaries,changed the grain preferred orientations,and notably increased the pole density ofαphase on the near surface from 2.41 to 3.46.The surface hardness values of the LSP samples increased with the increase of the number of shocks due to work hardening,while the LSP had a limited effect on the tensile properties.The high-cycle fatigue life of the LSP-treated sample was significantly enhanced by more than 20%compared with that of the untreated sample,which was caused by the suppression of the initiation and propagation of fatigue cracks.

脱脂花生粉特性对其挤压产品结构的影响

以低温脱脂花生粉为原料，采用DSE-25型双螺杆挤压实验室工作站，在花生粉高水分挤压组织化工艺优化的基础上，研究了原料特性（粒度、pH值和油脂含量）对挤压组织化产品结构的影响规律。结果表明，原料特性对脱脂花生粉挤压组织化产品的质量和结构有明显影响。粒径在0．2～0．3mm范围内的原料，其挤压产品既可保持适当的硬度和咀嚼度，又有较好的组织化结构，其微观结构细致，气腔小且分布均匀。原料的pH值对产品的流变学性质和微观结构影响较大；在花生蛋白等电点附近（pH值4．5），挤压产品的硬度和咀嚼度最高，具有较致密的组织结构；在接近中性时，组织化度最高；偏碱性条件不利于产品组织化结构的形成。随原料中油脂含量的增加，挤压产品的硬度、咀嚼度和剪切力均明显下降，扭矩显著降低；综合挤压产品的感官质量和质构分析结果，认为原料中油脂含量在3％-6％范围内，有利于挤压产品组织结构的改善和感官质量的提高。

Microstructure and high temperature oxidation resistance of Si-Y co-deposition coatings prepared on TiAl alloy by pack cementation process

In order to improve the high temperature oxidation resistance of TiAl alloy, Y modified silicide coatings were prepared by pack cementation process at 1030, 1080 and 1130 °C, respectively, for 5 h. The microstructures, phase constitutions and oxidation behavior of these coatings were studied. The results show that the coating prepared by co-depositing Si?Y at 1080 °C for 5 h has a multiple layer structure: a superficial zone consisting of Al-rich (Ti,Nb)5Si4 and (Ti,Nb)5Si3, an out layer consisting of (Ti,Nb)Si2, a middle layer consisting of (Ti,Nb)5Si4 and (Ti,Nb)5Si3, and aγ-TiAl inner layer. Co-deposition temperature imposes strong influences on the coating structure. The coating prepared by Si?Y co-depositing at 1080 °C for 5 h shows relatively good oxidation resistance at 1000 °C in air, and the oxidation rate constant of the coating is about two orders of magnitude lower than that of the bare TiAl alloy.

Structure uniformity and limits of grain refinement of high purity aluminum during multi-directional forging process at room temperature

The effect of forging passes on the refinement of high purity aluminum during multi-forging was investigated. The attention was focused on the structure uniformity due to deformation uniformity and the grain refinement limitation with very high strains. The results show that the fine grain zone in the center of sample expands gradually with the increase of forging passes. When the forging passes reach 6, an X-shape fine grain zone is initially formed. With a further increase of the passes, this X-shape zone tends to spread the whole sample. Limitation in the structural refinement is observed with increasing strains during multi-forging process at the room temperature. The grains size in the center is refined to a certain size （110 μm as forging passes reach 12, and there is no further grain refinement in the center with increasing the forging passes to 24. However, the size of the coarse grains near the surface is continuously decreased with increasing the forging passes to 24.

Effect of high temperature treatments on microstructure of Nb-Ti-Cr-Si based ultrahigh temperature alloy

To investigate the effects of homogenizing and aging treatments on the microstructure of an Nb-Ti-Cr-Si based ultrahigh temperature alloy,coupons were homogenized at 1 200-1 500 °C for 24 h,and then aged at 1 000 °C for 24 h.The results show that the heat-treated alloy is composed of Nb solid solution（Nbss）,（Nb,X）5Si3 and Cr2Nb phases.With the increase of heat-treatment temperature,previous Nbss dendrites transformed into equiaxed grains,and petal-like Nbss/（Nb,X）5Si3 eutectic colonies gradually changed into small（Nb,X）5Si3 particles distributed in Nbss matrix.A drastic change occurred in the morphology of the Laves phase after homogenizing treatment.Previously coarse Cr2Nb blocks dissolved during homogenizing at temperature above 1 300 °C,and then much finer and crowded Cr2Nb flakes precipitated in the Nbss matrix in cooling.Aging treatment at 1 000 °C for 24 h led to further precipitation of fine particles of Laves phase in Nbss matrix and made the difference in concentrations of Ti,Hf and Al in Nbss,（Nb,X）5Si3 and Cr2Nb phases reduced.

Creep properties and microstructure evolution of nickel-based single crystal superalloy at different conditions

The creep properties of nickel-based single crystal superalloy with [001] orientation was investigated at different test conditions. The microstructure evolution of γ′ phase, TCP phase and dislocation characteristic after creep rupture was studied by SEM and TEM. The results show that the alloy has excellent creep properties. Two different types of creep behavior can be shown in the creep curves. The primary creep is characterized by the high amplitude at test conditions of (760 °C, 600 MPa) and (850 °C, 550 MPa) and the primary creep strain is limited at (980 °C, 250 MPa), (1100 °C, 140 MPa) and (1120 °C, 120 MPa). A little change ofγ′precipitate morphology occurs at (760 °C, 600 MPa). The lateral merging of the γ′ precipitate has already begun at (850 °C, 550 MPa). Theγphase is surrounded by theγ′phase at (980 °C, 250 MPa). Theγphase is no longer continuous tested at (1070 °C, 140 MPa). At (1100 °C, 120 MPa), the thickness ofγphase continues to increase. No TCP phase precipitates in the specimens at (760 °C, 600 MPa), (850 °C, 550 MPa) and (980 °C, 250 MPa). Needle shaped TCP phase precipitates in the specimens tested at (1070 °C, 140 MPa) and (1100 °C, 120 MPa). The dislocation shear mechanism including stacking fault formation is operative at lower temperature and high stress. The dislocation by-passing mechanism occurs to form networks atγ/γ′interface under the condition of high temperature and lower stress.

Microstructure and evolution of(TiB_2+Al_2O_3)/NiAl composites prepared by self-propagation high-temperature synthesis

（TiB2＋Al2O3）/NiAl composites were synthesized by self-propagation high-temperature synthesis, and their phase compositions, microstructures and evolution modes were studied. The microstructures and shapes vary with the TiB2＋Al2O3 content in the NiAl matrix. TiB2 particles take a great variety of elementary shapes such as white bars, plates, herringbones, regular cubes and cuboids. These results outline a strategy of self-assembly processes in real time to build diversified microstructures. Some TiB2 grains in sizes of 2-5μm are embeded in Al2O3 clusters, while a small number of TiB2 particles disperse in the NiAl matrix. It is believed that the higher the TiB2＋Al2O3 content is, the more the regular shapes and homogeneous distributions of TiB2 and Al2O3 will be present in the NiAl matrix.

Microstructure evolution of a new directionally solidified Ni-based superalloy after long-term aging at 950 ℃ upto 1 000 h

The microstructure evolution of a new directionally solidified（DS） Ni-based superalloy used for gas turbine blades after long-term aging at 950 ℃ was investigated.The results show that the γ ＇ phase becomes more regular in dendritic arm and interdendritic area,while both the mass fraction and the size of γ ＇ phase increase gradually with increasing aging time.During long-term aging,the MC carbide dissolves on the edge to provide the carbon for the formation of M23C6 carbide by the precipitation of Cr at the grain boundary.The rose-shaped γ ＇/γ eutectic partly dissolves into γ matrix and the aging promotes it transform into raft-shape γ ＇.The microstructure is generally stable and no needle-like topologically close-packed phase（TCP） can be found after aging for 1 000 h.

Effects of Al and Mo on high temperature oxidation behavior of refractory high entropy alloys

Refractory high entropy alloys have superior mechanical properties at high temperatures, and the oxidation behavior of these alloys is very important. The present work investigated the high temperature oxidation behavior of three alloys with compositions of TiNbTa0.5Zr, TiNbTa0.5ZrAl and TiNbTa0.5ZrAlMo0.5, and the effects of alloying elements were discussed. Results indicated that the oxidation rates of the TiNbTa0.5Zr and TiNbTa0.5ZrAl alloys are controlled by diffusion, and obey the exponential rule. However, the oxidation rate of the TiNbTa0.5ZrAlMo0.5 alloy is controlled by interface reaction, and obeys the linear rule. The addition of Al leads to a better oxidation resistance by forming a protective oxide scale. However, the protection of Al-rich scale is weakened by the addition of Mo. Extensive pores and cracks occur in the oxide scale of the TiNbTa0.5ZrAlMo0.5 alloy, resulting in a significant decrease in oxidation resistance.

Formation mechanism of basin-like depression defect in electric upsetting process of Ni80A superalloy

A kind of surface instability,basin-like depression defect companied by mixed grain structure at the bottom of large-scale valve during electric upsetting process,would significantly influence the microstructures and mechanical properties of components.In order to analyze the forming process of the basin-like depression defect,a finite element model for the electric upsetting process of Ni80A superalloy was developed using multi-field and multi-scale coupling analysis method.Subsequently,a series of parameters loading path schemes for force and current were designed by varying the initial value,peak value and value level,and their effects on basin-like depression and mixed grain structure were simulated and uncovered.It is concluded that the changes of heating speed and pressurization speed result in the different flow velocities between the inner and outer layers of billet,thus exerting the basin-like depression.Simulation results also indicate that these defects can be optimized through the parameter coordination between force and current.Finally,the validity and reliability of the finite element model were verified by physical experiments in electric upsetting process.

Microstructure evolution of Al_(0.6)CoCrFeNi high entropy alloy powder prepared by high pressure gas atomization

The influence of cooling rate on the microstructure of Al0.6CoCrFeNi high entropy alloy（HEA） powders was investigated. The spherical HEA powders（D50≈78.65 μm） were prepared by high pressure gas atomization. The different cooling rates were achieved by adjusting the powder diameter. Based on the solidification model, the relationship between the cooling rate and the powder diameter was developed. The FCC phase gradually disappears as particle size decreases. Further analysis reveals that the phase structure gradually changes from FCC＋BCC dual-phase to a single BCC phase with the increase of the cooling rate. The microstructure evolves from planar crystal to equiaxed grain with the cooling rate increasing from 3.19×10^4 to 1.11×10^6 K/s.