Comparison of Size Characterization of Barley Starch Granules Determined by Electron and Optical Microscopy,Low Angle Laser Light Scattering and Gravitational Field-Flow Fractionation

Several methods were used for the characterization of starch granules isolated from barley kernels. A procedure based on a combination of alkaline digestion, toluene treatment and filtration over sieves with pore diameters of 70 and 40 μm was used for isolation and purification of starch granules from kernels. The released starch granules were characterized by various methods: scanning electron microscopy (SEM), image analysis of optical microscopy data (IAOM), low angle laser light scattering (LALLS), and gravitational field-flow fractionation (GFFF). All methods showed the bimodal size distribution of the isolated starch granules, however, they differed in the ratio of large and small starch granules. LALLS and GFFF were also used for determination of the ratio of large and small starch granules (ratio A/B) isolated from two malting barley cultivars Kompakt and Akcent. Both techniques determined the higher ratio A/B for the cultivar Akcent. SEM was also used to examine the extent of digestion. The micrographs indicate that a significant proportion mainly of small granules are still embedded into residues of endosperm and a more extensive digestion must be performed to release all starch granules from barley kernels.     

玉米淀粉的粒度效应对其糊化行为影响研究

研究和探讨了经过机械微细化处理的不同粒度玉米淀粉的糊化特性，结果表明，随着玉米淀粉粒度的降低，其糊化温度下降，糊化温度区间缩小，淀粉糊的粘度下降，但热糊稳定性增加。由于微细化处理后淀粉凝沉性增强，淀粉糊的透明度随淀粉粒度的下降而降低。     

声波粒度仪测量纳米级碳酸钙悬浊液中颗粒粒度分布

利用声波粒度仪对纳米级CaCO_3悬浊液中颗粒粒度分布进行了检测分析。实验结果表明,表面改性能够很好地改善纳米级CaCO_3在水中的润湿性及分散性,是实现纳米级CaCO_3悬浊液粒度分布有效测定的关键因素。另外,样品透射电镜分析结果表明,基于声衰减原理的声波粒度仪较好地反映了纳米级CaCO_3悬浊液中颗粒粒度分布情况。     

不同实验磨研磨的小麦粉的粒度分布

采用4种不同型号的实验磨研磨不同硬度的小麦,通过激光粒度仪测试小麦粉的粒度。结果表明,不同小麦粉的粒度差异较大,尤其是细小粉粒的分布很不均衡。采用光辊心磨的实验磨磨制的小麦粉,其细粉比例高于齿辊实验磨,但低于生产线小麦粉的细粉比例。小麦硬度越高其细粉比例越低。     

Barley Starch Granules Subject to SPLITT Cell Fractionation and Sd/StFFF Size Characterization

The coupling of two separation techniques is proposed as a methodology able to fractionate, starch granules of different botanical origins, both on preparative and analytical scale. The split flow thin cell (SPLITT cell) was optimized to produce a binary separation of the starch granules into two different size classes with a 5 μm cutoff point. The size separation was always better than 80%. The Sedimentation Steric Field Flow Fractionation (Sd/StFFF) provides sample particle size distribution (PSD) and is used here to control the SPLITT fractions. The proposed techniques, especially the former, are gentle and easy to use. Both the SPLITT and Sedimentation Fractionation results were checked by scanning electron microscopy (SEM). The procedure was originally applied to two samples from barley. The bimodal diameters were computed.     

小麦粉粒度变化与淀粉损伤程度

从小麦淀粉的原生态(粒径大小与分布)出发,首先拿等级粉的粗细度与之比较,分辨淀粉损伤的综合程度和倾向,进而对工艺中各研磨部位的面粉粒度、淀粉损伤程度进行分析研讨,以化验的量化结果,揭示淀粉损伤的真实面貌。紧紧抓住面粉粒度变化和淀粉损伤程度的同步因素,逐渐深入,诠释不被重视的等级粉淀粉损伤原因和专用粉能适应不同面制品要求的理论基础,提出了研究淀粉损伤和面粉粒度是制粉工艺研究的当务之急。     

Molar Mass Distribution and Size of Hydroxyethyl Starch Fractions Obtained by Continuous Polymer Fractionation

By the use of continuous polymer fractionation (CPF) the initial polymer can be separated into fractions of different molar masses, which makes it possible to obtain hydroxyethyl starch (HES) fractions tailor‐made for specific application. Two samples of HES (HES A and HES B) were fractionated by means of CPF. By size‐exclusion chromatography‐multi‐angle laser light‐scattering‐differential refractive index (SEC/ MALLS/DRI) measurements it was shown that CPF is able to remove the low‐molarmass components and to adjust the samples to various desired molar masses with lower polydispersities than the original samples. In terms of the weight‐average mean molar mass M_W , the sol fractions have smaller molar masses than the starting sample, whilst the gel fractions have higher molar masses. Furthermore the radius of gyration R_G could be determined for the initial sample HES B with 19.7 and 19.4 nm and also for some of its fractions. However, no general R_G—M_W relationship could be established for the HES samples fractionated using CPF. This is probably due to the complex branched structure of amylopectin. M_W and M_W/M_n of the six fractions obtained from HES A with M_W = 161, 000 g/mol and M_W/M_n = 4.7 ranged from 19, 000 to 362, 000 g/mol with M_W/M_n from 1.8 to 3.1. The molar masses of the four fractions obtained from HES B with M_W = 460, 000 g/mol and M_W/M_n = 6.0 were between 18, 000 and 680, 000 g/mol with M_W/M_n from 1.7 to 4.8 or between 202, 000 and 1, 005, 000 g/mol with M_W/M_n from 2.7 to 4.7 depending on fractionation strategy.     

润麦条件对面粉粒度分布的影响

面粉粒度对于面粉品质极为重要.在面粉加工过程中,润麦条件对面粉粒度有很大的影响,通过试验可知,润麦条件对面粉粒度分布影响大小为:对于B磨粉,含盐量5％能够使得粒度集中在-/11xx(筛网之上),其余含盐量能够使得粒度分布均匀;润麦时间30h可以显著提高筛上物粒度含量.对于M磨粉,含盐量5％和15％能够降低14xx/-(...     

Comparison of the GFFF and LALLS Methods for the Measurement of Starch Granule Size Distribution in Spring Barley Caryopses

A newly developed method GFFF (Gravitational Field‐Flow Fractionation) and the well known method LALLS (Low Angle Laser Light Scattering) were used to assess starch granule size distribution of ten varieties of spring barley. As a distribution criterion, the ratio of starch granule content larger than 8 μm (type A) and smaller than 8 μm (type B) was chosen. Both methods divided the observed set in a similar way. Varieties Akcent, Forum and Atribut formed a variety set with the highest ratio of large and small starch granules. Varieties Scarlet and Kompakt had intermediate ratios. The remaining five varieties Amulet, Novum, Olbram, Tolar and Krona had the lowest ratios of large and small starch granules. Statistical analysis showed that there was a highly significant correlation between the GFFF and LALLS methods.     

不同粒径分布对全籽粒玉米粉糊化特性的影响

分析不同粒径大小分布对不同淀粉含量全籽粒玉米粉糊化特性的影响,为其品质分析和加工提供参考依据。选取淀粉含量66%~77%的玉米,通过小型实验磨研磨得到不同粒径的全籽粒玉米粉,研究粒径大小分布、主要成分、损伤淀粉等指标对糊化特性的影响。结果表明,玉米粉的粒径大小和分布对其糊化能力、凝胶特性影响明显,特别是小颗粒粒径大小影响明显,但对回生老化特性影响不显著。平均粒径和小颗粒粒径越小、颗粒表面积越大时,越容易糊化,峰值黏度也越大,玉米粉间糊化能力差异越显著,总淀粉越多、脂肪和蛋白越少也越容易糊化,峰值黏度也越大;小颗粒粒径越小、比表面积越大,凝胶抗剪切能力越差,玉米粉间凝胶特性差异越明显,总淀粉和损伤淀粉含量升高、脂肪和蛋白质降低,也降低凝胶抗剪切能力;粒径大小与分布对玉米粉回生老化特性影响不显著,总淀粉和直链淀粉增加、脂肪减少,提高凝胶回生能力。     

Formation of Vitamin E Emulsion Stabilized by Octenylsuccinic Starch: Factors Affecting Particle Size and Oil Load

Vitamin E (VE) emulsions were formed by adding VE acetate in an octenylsuccinic (OS) starch solution with distilled water and homogenizing with a microfluidizer at 20000 psi. The objective of this study was to investigate the effects of total concentration of starch and oil, ratio of oil to starch, pH value, and free OS content on emulsion properties. A method using HPLC was developed to analyze VE in emulsion, and the results were used to estimate the amount of surface VE oil. Lower total concentration of starch and oil and lower ratio of oil to starch resulted in more stable emulsions, whereas differences in the pH between 3 and 8 had little effect. Free OS content increased with greater particle size and decreased oil load. Increasing the number of passes reduced the initial particle size of the emulsion but increased free OS content.     

光散射及其在大豆蛋白粒度分析中应用

该文简要介绍光散射技术及其在粒度测试中应用,并就大豆分离蛋白样品加热前后粒度变化,应用激光光散射仪,分析大豆分离蛋白加工和热处理过程中聚集体的形成和变化。     

含氟乳液粒径及其分布的影响因素探讨

运用种子乳液聚合法制备了皮革填充含氟微乳液。FTIR光谱的测试表明:含氟单体参与了聚合反应。运用Autosizer(MalvernⅡC)粒径分析仪,研究聚合工艺中以不同比例的乳化剂、N-羟甲基丙烯酰胺(NMA)用量、聚合温度、中和温度对乳胶粒径及其分布的影响。结果表明:SLS/OP比值为1.5,NMA用量质量分数为4%,聚合温度为55℃,中和温度在50~55℃之间时,能制备出粒径小、分布均匀的含氟微乳液。     

Microfluidizer对膳食纤维微粒粒度分布的影响

采用Nicomp380粒度分析仪,对应用Microfluidics公司生产的微射流均质机处理前后的膳食纤维溶液中微粒粒度分布的影响进行分析,结果显示:破碎后的微粒体系出现再团聚现象;不同压力,不同次数等条件处理下微粒粒度分布存在显著差异。     

蕨根淀粉的组分分离和纯化研究

以蕨根淀粉为原料,采用有机溶剂低温重结晶法和凝胶色谱分析对蕨根淀粉的分级和纯化进行了研究。结果表明:用正丁醇重结晶法重结晶8次和5次,可以得到高纯度的蕨根直链和支链淀粉。蕨根直链淀粉和支链淀粉与碘络合物的最大吸收波长分别为640 nm和547 nm,直链淀粉和支链淀粉的蓝值分别为0.91和0.13,均处于相应的分布范围,表明纯化后蕨根直链和支链淀粉的纯度高。蕨根直链淀粉和支链淀粉的分子质量范围均小于玉米直链淀粉和支链淀粉。采用分光光度法测定蕨根淀粉含直链淀粉为25.38%,高于玉米淀粉的20.33%。     

小麦粉粒度研究综述

小麦粉粒度是小麦粉的一个重要物理参数,它对小麦粉以及面制食品的品质产生很大的影响。小麦粉粒度的分布与小麦的品质和研磨方法有关。当小麦粉粒度变化时,小麦粉的组成成分以及物理特性也会发生变化,从而对面制品的品质产生影响。阐述了小麦粉粒度、小麦粉粒度分布以及当小麦粉粒度变化时,小麦粉的组成成分的变化等几个方面内容,同时介绍了小麦粉粒度的测定方法、小麦粉粒度在小麦硬度研究方面的应用和小麦粉粒度对面制品品质的影响。     

淀粉粒度特点及对其加工特性影响的研究进展

天然淀粉颗粒通常以特定形状、大小和数量比例存在根、茎、籽粒等作物组织。生产经验表明粒度对天然淀粉原料的加工及制成品品质特性影响显著。同一原料不同粒度淀粉粒的化学组成和聚集态结构差异较大,其糊化、老化、胶凝、酶解等加工性能也不同。将天然淀粉原料按粒度进行分级、复配重组,是改善淀粉原料特性和扩展其加工用途的重要手段之一。本文全面剖析粒度对淀粉组成及理化性质的影响及其变化规律,旨在揭示淀粉粒度-性能关系和为淀粉原料分级利用提供理论参考。     

晶浆黏度对谷氨酸结晶晶习及粒度分布的影响

用不同浓度的蔗糖溶液制备不同黏度梯度的溶液,考察了黏度对谷氨酸结晶晶习及粒度分布的影响,并通过测定不同黏度条件下谷氨酸结晶诱导期时间及生长速率的变化,探寻了黏度对谷氨酸结晶的影响机理。实验表明,在实验所测的黏度范围(1.00～10.30mP·s)内,黏度对谷氨酸的晶习基本没有影响,在相同过饱和度下,黏度增加,谷氨酸结晶诱导期时间延长,结晶成核速率减小,谷氨酸晶体的生长速率减小,使得谷氨酸晶体的颗粒直径减小,但晶体粒度分布均匀性略有增加。在工业生产上可以适当地提高结晶温度,以降低溶液的黏度,缩短结晶的诱导期时间,提高晶体的生长速率,使其更有利于谷氨酸的结晶。     

Effects of Granule Size and Size Distribution on Rheological Behavior of Chemically Modified Potato Starch

The effects of granule size and size distribution on rheological behavior of hydroxypropylated and phosphate cross‐linked potato starch (HPS) were studied by steady and dynamic viscoelasticity measurements. The rheological behavior of starch dispersions was strongly influenced by granule size and granule‐to‐granule interaction. Average granule size of HPS dispersion at high concentration was smaller than that at low concentration. Time dependence of viscosity was quite different depending on shear rate; thixotropy at low shear rates and antithixotropy at high shear rates. At higher concentrations, HPS dispersion showed a non‐Newtonian behavior, and it tended to a Newtonian behavior when concentration was lowered. Yield stress and creep recovery of HPS dispersion at higher concentrations was more pronounced than those at lower concentrations.     

Starch Granule Size Strongly Determines Starch Noodle Processing and Noodle Quality

Chemical compositions, physical properties, and suitability for starch noodle making of different granule size fractions from potato and sweet potato starches were studied. The ash content, amylose content, phosphorus content, gel firmness, and freeze‐thaw stability of small‐size granule fractions(< 20 μm) were significantly different from those of the large‐size granule fractions. The processibility and the qualities evaluated by objective and subjective methods of both dried and cooked starch noodles made from small‐size granule fractions were significantly better than those made from their initial starch preparations and much better than those made from the large‐size granule fractions.