小麦胚乳A、B型淀粉粒的形成与生长特征及氮素调节

为研究小麦胚乳淀粉粒形成与生长特征,以优质小麦品种藁城8901为材料,在缺氮(对照)和施氮条件下,对籽粒发育过程中淀粉粒的产生、体积与数目分布及粒径变化进行比较。结果表明,花后4 d,小麦胚乳已出现A型淀粉粒,其中施氮处理粒径显著高于对照,说明氮素有利于早期淀粉粒的产生。花后10 d,又产生了一个新的小淀粉粒群体,即B型淀粉粒。花后10~12 d,施氮处理的粒径显著低于对照,可能是这个阶段施氮能促进小麦产生了更多的小(B型)淀粉粒,说明这个时期淀粉粒的生长以数目增长为主。花后14~17d,施氮处理淀粉粒粒径显著高于对照,说明这个时期淀粉粒生长以个体体积增大为主。花后24 d,0.8μm淀粉粒数目急剧增加,表明此期又产生了一个小淀粉粒群体。花后28 d,施氮处理0.8μm淀粉粒数目仍不断增加,表明施氮能促进灌浆后期籽粒产生更多的小淀粉粒。通过透射电镜观察发现,小淀粉粒是由大淀粉粒分裂而来的,单个存在。小麦胚乳A型淀粉粒形成和发育时期基本在花后14 d之前,而B型淀粉粒在成熟前,其体积和数目一直在增加。施氮有利于胚乳A、B型淀粉粒个体的增大和数目的增多。     

全支链小麦A-型淀粉与B-型淀粉部分理化性状的比较

全支链小麦淀粉具有两种不同形态的淀粉颗粒,二者具有不同的颗粒度分布、白度以及支链淀粉含量。研究表明：全支链小麦A-型淀粉比全支链小麦B-型淀粉有更大的等价粒径、更高的白度和较低的支链淀粉含量;触变性分析显示全支链小麦B-型淀粉比全支链小麦A-型淀粉有更趋于牛顿流体的行为和相对较小的表观黏度。     

小麦淀粉大颗粒和小颗粒(A-型颗粒和B-型颗粒)的分离纯化与理化性质差异综述

成熟的小麦(Triticurn小麦L.)胚乳中至少含有2种不同的淀粉颗粒群体:大的A-型淀粉颗粒和小的B-型淀粉颗粒。综述了小麦淀粉A-、B-型淀粉颗粒的分离纯化方法,并分析了两者理化性质的差异。     

百合化学成分及其淀粉粒结构与一般特性

对百合基本成分、淀粉粒的表面与晶体结构以及其淀粉的一般特性进行了系统研究，结果显示：百合含有丰富的淀粉、蛋白质与果胶，脂肪含量低；百合淀粉粒具有多种形态，粒径范围宽（10μm-105μm），平均粒径为35μm。百合淀粉粒具有典型的晶体结构特征，晶型为B-型；百合淀粉溶解度和膨润力较马铃薯淀粉与玉米淀粉大；百合淀粉的抗冻稳定性较马铃薯淀粉与玉米淀粉差。     

小麦A-型及B-型淀粉对面粉糊化特性及面团流变学特性的影响

采用分离重组的方法,使B-型淀粉占总淀粉的质量百分比分别为0%、5%、10%、15%、20%、25%、30%、35%、40%、45%、50%、60%,探究不同小麦A-型及B-型淀粉比例下形成重组面粉的糊化特性及面团流变学特性的变化规律。结果表明,随着B-型淀粉颗粒配比的增加,重组面粉的糊化温度呈上升趋势,B-型淀粉从0%增加到40%时无显著性差别。峰值黏度、最低黏度、最终黏度均呈下降趋势;重组面粉吸水率显著性增大,形成时间呈整体上升趋势,面团的稳定时间呈下降趋势,弱化度总体呈波动性上升趋势,B-型淀粉配比为0%时有最小值,在50%~60%范围时弱化度最大,当B-型淀粉占总淀粉比例为30%~50%时,其粉质指数较大且无显著性差异;面团发酵最大高度(Hm)、面团最终高度(h)的变化趋势基本一致,呈现出总体下降趋势。气体释放曲线最大高度(H’m)、面团的产气量(V总)、面团气体的损失量(V损)有着基本一致的变化趋势,当B-型淀粉配比在0%~20%范围时,均呈现出先增大后减少的趋势,随着配比的增大(20%~60%)总体呈小范围内波动性增加,但面团的持气率R有着完全相反的趋势。且当B-型淀粉占总淀粉比例为20%时,面团的产气量V总和气体损失量V损最小,面团的持气率R最大。     

A-型淀粉球晶的制备及表征

通过盐酸的温和酸解作用，使玉米淀粉颗粒的无定型区域水解，得到结晶度较高的酸解淀粉。将该酸解淀粉溶解后冷冻重结晶，制备出B-型球晶，在此基础上进一步重结晶制备得到了A-型淀粉球晶。用扫描电子显微镜(SEM)、X-射线衍射、热重分析法(TG)以及凝胶渗透色谱(GPC)等方法对所得的淀粉球晶进行了表征。结果表明所得A-型球晶的平均粒径约为3μm，晶体形态为A型、其热分解起始温度低于天然淀粉而高于酸解淀粉和B型球晶，组成球晶的淀粉分子链长度约为14个葡萄糖单元。     

小麦淀粉悬浮液沉淀的机理分析与速沉技术探讨

在小麦淀粉生产中,淀粉悬浮液(指分离面筋后的淀粉溶液、亦称淀粉浆)的沉淀分离是整个工艺过程的关键环节之一。由于小麦淀粉颗粒的直径大小悬殊、水溶性蛋白和淀粉颗粒一起分散在溶浆中、因而小麦淀粉浆的沉淀、分离一直比较困难。     

糯玉米淀粉形成过程中理化特性的变化

为阐明糯玉米淀粉形成过程中理化特性的变化趋势。以6个糯玉米品种为材料,研究了其在花后7 d(淀粉初始期)、22 d(乳熟期)、40 d(成熟期)的淀粉理化特性。结果表明,新形成的淀粉粒为圆型或椭圆型,表层光滑,而鲜食期和成熟期淀粉粒呈不规则的多面体,表层粗糙。淀粉粒径和尖峰强度随生育进程推进逐渐加大(升高)。最大吸收波长和碘结合力以新形成的淀粉粒最高,其次是成熟期。RVA和DSC特征参数在不同生育阶段的变化品种间有显著差异。总体上,随着发育进程推进,淀粉峰值黏度、崩解值、热焓值和回生热焓值先升后降,而回生值、糊化和峰值温度逐渐下降。淀粉形成过程中淀粉粒形态、大小、晶体结构和链长分布发生变化,改变了淀粉糊化和热力学特性。     

小麦A、B型淀粉分离提取方法研究

该研究对小麦A、B型淀粉分离提取方法进行探讨,结果表明,采用水柱沉淀离心法,在淀粉浆浓度0.1 g/mL、离心速度200 r/min、静置时间40 min和静置次数3次条件下,可快速、有效分离A、B型淀粉;A、B型淀粉得率分别为74.2%和23.7%,淀粉损失2.1%。经显微照相显示,此条件下A、B型淀粉分离彻底。     

复合酶法改性糯麦A-、B-型淀粉及对其结构和消化特性的影响

以从糯麦淀粉中分离所得的A-、B-型淀粉为研究对象,并以此作为受体,高直链玉米淀粉为供体,利用普鲁兰酶和分支酶协同处理对糯麦淀粉进行改性,测定其颗粒形态、结晶结构以及表观直链淀粉含量、溶解度、膨胀力等理化性质,并对其消化特性进行考察。结果表明：采用普鲁兰酶和分支酶两种复合酶法改性的糯麦A-、B-型淀粉,其预测血糖指数显著降低,表观直链淀粉含量显著增加、溶解度随着温度的增加而变大,膨胀力随着温度的增加基本保持不变。采用扫描电子显微镜观察到酶法改性后的淀粉颗粒形态出现孔洞结构,利用X射线衍射和傅里叶红外光谱分析相对结晶度和1 047 cm－1/1 022 cm－1处的比值可得,复合酶改性淀粉的长程有序结构和短程有序结构显著改善。通过普鲁兰酶预处理后再用分支酶改性,对糯麦A-型和B-型淀粉进行结构修饰,能够显著改善其消化特性。     

超微全藕粉与藕淀粉颗粒结构的比较研究

应用光学显微镜、扫描电子显微镜、偏光显微镜和X-射线衍射仪对藕淀粉和不同粒度超微全藕粉的颗粒形态和表面结构进行了比较研究。结果表明,藕淀粉颗粒表面光滑,大多呈棒状,少部分呈椭圆形或圆形,有明显的环纹,粒心偏于颗粒的一端,偏光十字明显,颗粒较大的棒状藕淀粉呈“X”形,颗粒较小的椭圆形或圆形藕淀粉呈垂直十字形或斜十字形,部分呈“X”形,X-衍射图谱为B型。全藕粉经过超微粉碎后,大部分藕淀粉颗粒被破坏,少数藕淀粉颗粒完整,只能看到部分未被破坏的棒状藕淀粉颗粒的“X”形或残缺的“X”形以及部分小颗粒藕淀粉的十字,不同粒度的超微全藕粉随着粒度的减小,结晶区域减小,而非结晶区域增大。     

Comparative studies on morphological and crystalline properties of B-type and C-type starches by acid hydrolysis

Comparative studies on acid hydrolysis of B-type Fritillaria starch and C-type Rhizoma Dioscorea and Radix Puerariae starches were carried out using a scanning electron microscope (SEM) and X-ray diffraction (XRD). Fritillaria, Rhizoma Dioscorea and Radix Puerariae starches were hydrolyzed with 2.2 mol/L at 35 °C for 2, 4, 8, 16 and 32 days, respectively. The SEM and XRD results revealed that B-type starch and C-type starch displayed different hydrolysis mechanisms. The acid corrosion started from the exterior surface of B-type starch granules followed by the interior core of starch granules. However, the hydrogen ion primarily attacked the interior of the C-type starch granules and then the exterior of starch granules. B-type starch granule started to crack at the hydrolysis period of 4 days while C-type starch granule was not cracked until the hydrolysis progressed up to 16 days. The crystalline type of B-type starch was not changed with increasing hydrolysis time. However, the crystalline type was gradually changed from C-type to A-type for the Rhizoma Dioscorea and Radix Puerariae starches with increase in the hydrolysis time. This result showed that the B-type polymorphs present in the C-type starch granule was preferentially hydrolyzed during the first stage of hydrolysis.     

化学糊化法研究乙酰化马铃薯淀粉的性质

室温下用4mol/L CaCl2溶液对乙酰化马铃薯淀粉颗粒外围进行化学糊化,去除外围糊化物后得到残存颗粒。对乙酰化马铃薯淀粉原颗粒和残存颗粒的粒径、取代度、结晶性质以及热性质进行分析比较,结果表明：用乙酸酐制备的乙酰化马铃薯淀粉的取代度与淀粉颗粒的大小相关,颗粒越小,取代度越大。乙酰基团在颗粒中分布不均匀,大多分布在淀粉颗粒的外围。残存颗粒与原颗粒晶型相同,均为B-型;淀粉颗粒糊化程度越高,所得残存颗粒的相对结晶度和糊化峰值温度越大。     

四种元麦淀粉粒形态结构与理化性质的比较

为探明不同品种元麦淀粉粒形态结构与理化性质的差异,以通麦6号、苏裸麦2号、青元麦、黑元麦为实验材料,采用扫描电镜观察、X-射线衍射、傅里叶变换远红外光谱等方法研究了这四类元麦淀粉粒形态特征及其理化性质,结果表明:青元麦,苏裸麦2号和通麦6号淀粉颗粒比较光滑,大小比较均匀,大颗粒多为圆饼形,小颗粒多为圆球形。黑元麦颗粒大小不均匀,差异较大。4类元麦的表观直链淀粉含量不同,其中黑元麦的直链淀粉含量显著高于其他品种;黑元麦和苏裸麦2号的B-型淀粉粒较多,通麦6号和青元麦的A-型淀粉粒较多。黑元麦的淀粉相对结晶度和表层结构有序度最高,溶解度最高、膨胀势最低。在淀粉葡萄糖苷酶水解过程中,青元麦水解程度最高,苏裸麦2号水解程度最低;在猪胰腺α-淀粉酶水解过程中,通麦6号水解程度最高,青元麦最低;在HCl水解过程中,青元麦水解程度最高,黑元麦水解程度最低。     

Effect of damaged starch on the rheological properties of wheat starch suspensions

The influence of damaged starch content on particle size distribution and rheological properties of unheated starch suspensions and pasting properties were investigated. Four samples containing different amounts of damaged starch were studied. Particle size distribution curves shifted toward higher diameters, and a greater overlap of both populations of particles (A- and B-type granules) and a decrease of both peak heights were produced. The flow curves of unheated starch suspensions were fitted using the power law model. The flow behavior indexes were higher than the unit. The consistency coefficient increased with the increment of damaged starch content. Unheated starch suspensions showed time-dependent rheological behavior and were described by the Weltman model. The unheated suspensions exhibited a thixotropic behavior. With regard to the pasting process, the increment of damaged starch content produced gradual reductions in peak viscosity, final paste viscosity, breakdown and setback. Results demonstrated the importance of the presence of physically damaged granules in wheat starch rheological characteristics.     

Characteristics of native and enzymatically hydrolyzed Zea mays L., Fritillaria ussuriensis Maxim. and Dioscorea opposita Thunb. starches

Comparative studies on glucoamylase hydrolysis of A-type Zea mays L., B-type F. ussuriensis Maxim., and C-type Dioscorea opposita Thunb. were carried out by scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared (FT-IR) spectra and differential scanning calorimetry (DSC). Maize, Fritillaria, Dioscorea starches were hydrolyzed with glucoamylase for 2, 4, 8, 12 and 24 h, respectively. The SEM and XRD results revealed that A-type, B-type starch and C-type starch displayed different hydrolysis mechanisms. A-type starch was digested with enzyme penetrating into starch granules through natural pores on the surface and disrupted the interior of the starch granules. The glucoamylase worked by attacking the surface of B-type starch and forming cracks. When endo-corrosion occurred, the internal part of the granule was corroded through small cracks. However, the glucoamylase primarily attacked the interior of the C-type starch granules and then the exterior of starch granules. FT-IR confirmed that the amorphous regions in the starch granules are firstly hydrolyzed and could be hydrolyzed completely as long as the hydrolysis time is sufficient. The transition temperatures and enthalpy of gelatinization (ΔH_gel) were determined using DSC. According to the gelatinization parameters, it could be further proved amorphous and crystalline structures were hydrolyzed.     

Supramolecular structure of A- and B-type granules of wheat starch

The supramolecular structure of the A- and B-type granules of wheat starch was compared. Polarized light microscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to study the granular, crystalline, and short-range structures. The A- and B-type granules displayed a typical A-type crystalline structure with the degrees of crystallinity of 31.95% and 29.38% respectively. In addition, the B-type granules had some V-type crystallites. The nanostructure and fractals were characterized by small angle X-ray scattering (SAXS), which showed that the average thickness of the lamellae of the A-type granules was larger, while the B-type granules possessed a higher degree of ordering in the lamellar regions. A second order reflection was found in both A- and B-type granules, which was proposed due to the crystalline lamellae of the semicrystalline lamellae. The A- and B-type granules had mass and surface fractal structures respectively.     

种植密度对沿淮玉米籽粒淀粉粒度分布与糊化特性的影响

分析不同种植密度对沿淮玉米籽粒中淀粉粒度分布与糊化特性的影响。以豫单132、京科968等13个玉米杂交品种为材料,设置56 250 株/hm2、67 500 株/hm2、77 250 株/hm2等3个种植密度,分析不同种植密度对玉米籽粒品质、淀粉粒度分布与糊化特性的影响。结果表明,在种植密度56 250~77 250 株/hm2范围内,随着种植密度的增加,玉米籽粒的蛋白质和脂肪含量呈递减趋势,淀粉含量呈递增趋势,即淀粉/蛋白质比率增加。玉米籽粒大型淀粉粒体积和表面积百分比显著增加,小型淀粉粒却显著降低。增加种植密度后玉米淀粉的峰值黏度、低谷黏度、最终黏度和稀懈值等黏度参数均呈显著升高。相关分析表明,玉米籽粒峰值黏度等黏度参数与小、大型淀粉粒体积百分比呈正相关,与中型淀粉粒体积百分比呈显著或极显著负相关。说明种植密度影响玉米籽粒淀粉粒度分布、淀粉黏度参数和组分含量。     

海藻酸钠结合超低温冷冻处理对甘薯淀粉颗粒结构和性质的影响

为改善甘薯淀粉耐低温、耐热和抗剪切稳定性,通过测定甘薯淀粉颗粒的粒度分布、观察微观结构并测定结晶特性、热力学特性以及糊化特性,研究不同冷冻温度和添加海藻酸钠处理对甘薯淀粉颗粒尺寸、结晶结构、表面结构、糊化性质和热性质的影响.结果表明,冷冻温度由-20℃降至-80℃时,甘薯淀粉颗粒粒径减小,淀粉颗粒表面由数量少的大孔洞转...     

Milling of rice grains: The roles of starch structures in the solubility and swelling properties of rice flour

Rice flours with different particle sizes and degrees of damaged starch granules were produced by hammer milling and cryogenic milling of rice grains, where degradation of starch molecules was evident in the hammer‐milled flours, but not in the cryogenically milled flours. The solubility and swelling properties of the resulting rice flours were determined in cold (30°C) and hot water (90°C). The cold‐ and hot‐water starch solubility was strongly correlated with the degree of damaged starch granules, and weakly with the particle size of rice flour. No evident correlations were observed between starch solubility and the molecular structures, indicating that molecular degradation by milling process was not the only precondition of increased starch solubility. Possible mechanism for the observed correlations is that increasing surface area and/or exposure of loosely packed inner part of starch granules with increasing degree of damaged starch granules allowed more starch molecules to leach out in cold and hot water. Furthermore, the cold‐water swelling of rice flour was strongly correlated with the degree of damaged starch granules, possibly due to the rapid hydration of damaged starch granules, whereas the hot‐water swelling did not show any correlations with flour particle size and granular and molecular starch structures. The results have provided better insights in the relationship between starch structures and solubility and swelling properties of rice flour, which can be used to improve the manufacture and selection criteria of rice flour for better products.