软质小麦与硬质小麦的籽粒结构比较研究

用扫描电镜观察三个小麦品种（２软质１硬质）的籽粒结构结果表明，硬质小麦淀粉粒较小，胚乳中淀粉与蛋白质基质密结，导致磨粉时破损淀粉粒较多，胚乳也易于与麸皮分离，出粉率高，麸星较少。而软质麦淀粉粒较大，淀粉粒与基质蛋白质结合不牢固，磨粉时易于分离，淀粉粒破碎少，且麸星较多，总出粉率低。     

烟台地区小麦硬度指数调查分析

<正>采用硬度指数法对烟台地区2015年种植收获的鲁麦21、烟农24、烟农999、烟农5158、济麦22、胶州22六个主要品种的小麦进行小麦籽粒硬度测定,为2015年度入库小麦品质判定和质量控制提供参考,也为小麦种植品种选择提供部分数据参考。小麦硬度即小麦胚乳质地,是指小麦籽粒抵抗外力作用下发生变形和破碎的能力,即破碎小麦籽粒时所需要的力。小麦硬度受遗传控制,不同品种的小麦胚乳细胞中蛋白质基质和     

小麦籽粒硬度与淀粉粒蛋白关系的研究和应用

从小麦籽粒硬度与淀粉粒蛋白的相互关系的角度，详细介绍了国内外有关小麦硬度、小麦淀粉粒与蛋白质之间的相互作用、小麦籽粒硬度遗传控制、小麦淀粉粒表性特征对食品质构的影响等的最新研究成果，为客观评价小麦籽粒的硬度、了解小麦淀粉粒蛋白在面团形成过程中的功能，从而帮助育种工作者和谷物生产者更有效地为小麦加工利用提供理想水平的小麦原料、为小麦品质改良研究提供参考依据。     

不同活力种子对玉米产量与淀粉品质的影响

以玉米杂交种安科985和隆平206为材料，分析不同种子活力水平(相对发芽率100%、80%和60%)间玉米籽粒产量、淀粉粒度分布和黏度特性的差异。随着种子活力的降低，2个玉米品种穗长、百粒重、穗粒重、产量都呈降低的变化趋势，玉米胚乳大型淀粉粒组体积分布与数量分布的百分比显著减小(P<0.05),而淀粉粒表面积百分比显著增大(P<0.05),可见低活力种子不利于玉米胚乳淀粉粒个体体积增大。活力对籽粒淀粉含量的影响最大，蛋白质含量次之，脂肪含量相对较小。大型淀粉粒组(直径>16μm)的表面积分布百分比与淀粉稀懈值和峰值黏度呈显著负相关(P<0.05)。低活力种子，通过影响胚乳淀粉粒度分布，即减小大型淀粉粒比例，从而降低了玉米淀粉最终黏度、峰值黏度等糊化参数。     

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。     

高、中、低筋力小麦胚乳不同部位蛋白体积累研究

为探明不同面筋强度的小麦胚乳不同部位蛋白体积累的差异,本研究以徐麦30(高筋)、扬麦11(中筋)、扬麦13(低筋)小麦为试验材料,从微观结构角度研究了不同筋力小麦胚乳背部和腹部蛋白体大小、面积及积累的差异。结果表明:1)小麦胚乳腹部蛋白体积累速率呈现先慢后快的积累变化,不同筋力小麦表现为徐麦30扬麦11扬麦13,且在花后8、11和14 d达显著差异;2)花后11、14、17 d为胚乳背部蛋白体的快速积累期,不同筋力小麦蛋白体积累量表现为徐麦30扬麦11扬麦13,尤以花后11、14和17 d突出;3)同一品种胚乳腹部和背部蛋白体积累量不同,表现为腹部背部,且差异显著;4)花后14~17 d是小麦胚乳积聚蛋白质速率最快的时期,细胞内含有较多的大蛋白体或蛋白聚积体且分布较集中;5)成熟籽粒中不同筋力小麦蛋白体和淀粉体分布不同。高筋小麦蛋白体分布较多,与淀粉粒结合程度最高,而低筋小麦蛋白体分布最少,且淀粉体之间空隙较大。中筋小麦蛋白体和淀粉体分布介于两者之间。     

彩色小麦的理化特性及麸皮粉的品质评价

目的研究彩色小麦和普通小麦的理化特性、营养组成及小麦皮层和胚乳中淀粉粒的结构形态和类型,为进一步了解彩色小麦的特性提供理论依据,为彩色小麦的营养加工奠定良好的基础。方法采用国标方法,对彩色小麦的理化指标和营养组成进行综合分析;采用扫描电子显微镜方法观察分析彩色小麦的皮层和胚乳中淀粉粒的结构形态和类型。结果彩色小麦在千粒重、容重等物理特性方面低于普通小麦,且彩色小麦籽粒的长宽比大,没有普通小麦籽粒饱满。在营养组分方面,绿麦3104、紫麦3202、黑麦3201的蛋白质含量分别比普麦烟农19高29.5%、24.4%、21.3%;湿面筋含量分别比普麦烟农19高29.6%、19.0%、17.0%;粗脂肪含量分别比普麦烟农19高31%、10.4%、22.2%。通过扫描电镜对小麦皮层结构分析发现彩色小麦糊粉层中含有大量的糊粉颗粒,集中了小麦籽粒大部分的营养物质。干法制备的麸皮粉,随着碾磨道数的增加,其灰分含量呈升高趋势,出粉率和白度呈降低趋势。结论彩色小麦在营养组成方面与普通小麦相比有很大优势,麸皮粉的品质特性与普通小麦相似,但彩色小麦的胚乳淀粉粒的形态和类型与普通小麦存在很大差异。     

RNAi 靶向沉默opaque2基因对高粱醇溶蛋白含量的影响

为研究opaque2基因沉默对高粱醇溶蛋白含量的影响,采用RNAi技术构建opaque2基因抑制表达载体,利用农杆菌介导转化高粱幼胚,测定转基因植株籽粒中醇溶蛋白含量,SDSPAGE电泳检测醇溶蛋白带型,并使用透射电镜观察胚乳细胞中蛋白质体变化。结果表明,与野生型相比,5株转基因植株中4株籽粒的醇溶蛋白含量显著降低(P0.05);野生型和各转基因植株的醇溶蛋白SDS-PAGE电泳带型相同;野生型胚乳细胞中淀粉粒排列紧密,部分大淀粉粒融合成大块状,蛋白质体数量较多且有一些体积较大;而转基因植株淀粉粒排列疏松,细胞中存在多处孔隙,蛋白质体数量较少,体积较小。opaque2基因沉默引起胚乳细胞蛋白质体数量变少,体积变小,进而影响胚乳细胞内部结构和籽粒醇溶蛋白含量。     

玉米角质和粉质胚乳淀粉粒粒径、糊化特性及凝胶质构特性的研究

以莱农14、青农105、连胜15、隆平206和先玉335玉米为材料,人工分离角质和粉质胚乳,通过显微镜观察淀粉粒粒径,采用快速黏度测定仪(RVA)和物性测试仪(TPA)分析糊化特性和质构特性,比较玉米角质和粉质胚乳淀粉粒粒径、糊化特性和质构特性的差异。结果表明,角质胚乳淀粉粒平均粒径显著大于粉质胚乳;角质胚乳的峰值黏度、崩解值和凝胶回复性显著低于粉质胚乳,峰值时间和糊化温度显著高于粉质胚乳,而凝胶的硬度、弹性、凝聚性、胶着性和咀嚼性除了与胚乳质地有关外,也受品种的影响。在玉米实际加工利用时,可以根据需要选择不同类型的胚乳,以实现玉米胚乳的合理有效运用。     

不同种植密度对夏玉米胚乳细胞淀粉粒分布及形态的影响

以郑单 958为材料,通过不同种植密度,利用激光衍射粒度分析仪、扫描电镜及透射电镜, 分析不同种植密度夏玉米胚乳籽粒淀粉粒粒度分布特征。结果表明, 不同种植密度玉米籽粒淀粉粒的粒径下限一致 (0.38 μm),上限D1 > D2 > D3;体积、表面积及数目均值：D2 > D3 > D1。从淀粉粒的扫描图可以看出不同处理淀粉粒形态及胚乳细胞内其他内含物含量均有差异。从淀粉粒的透射图可以看出,各处理间淀粉粒的发育、外形、排列以及其他质体的数量都存在较大差异;密度可以调节玉米胚乳淀粉粒的分布及形态。     

The influence of the physical structure of the protein matrix on wheat hardness

The influence of a range of factors on wheat hardness was investigated with particular reference to the physical structure of the endosperm protein matrix. Differences in hardness were found to involve the continuity of the protein matrix and the strength with which it physically entrapped starch granules. The primary determinant of wheat hardness is genetically controlled and appears to relate to factors influencing the degree of compactness of endosperm cell components. Environment and protein content are also of significance in determining the extent to which an ordered structure forms.     

The conditioning of wheat. The effect of increasing wheat moisture content on the milling performance of uk wheats with reference to wheat texture

Five UK wheats of similar protein content but widely different degrees of hardness have been conditioned, using two lying times, to give wheat moisture contents in the range 14–16%. The milling performance of the wheats has been assessed in terms of extraction rate, flour moisture content, grade colour figure (GCF) and ash content. Extraction rates all decreased in a linear manner with increasing wheat moisture content. The hard wheats tolerated added water far better than the soft wheats. Hard wheats exhibited a smaller extraction rate loss than the soft wheats for each additional 1% wheat moisture content. Flour moisture contents increase with increasing wheat moisture content and a measure of the moisture losses is obtained for the laboratory milling system. GCF and ash fell with increasing wheat moisture content (decreasing extraction rate). When extraction rates are based on wheat at a fixed moisture content the hard wheats showed very small gains in milling yield but soft wheats suffered a reduction in milling performance as wheat moisture increased.     

Wheat endosperm hardness. Part I. Relationships to colour of kernel cross-section

The aim of this study was to determine to what extent the measurement of wheat endosperm colour can be used to predict its hardness. The results indicate that there is no general (for all varieties) relationship between the colour of wheat endosperm and its hardness. Nevertheless, endosperm hardness tends to increase along with increasing values of b*, H and S attributes and decreasing values of a*. More promising results were obtained when the colour–hardness relationship was examined within a variety. In all cases, the results were statistically significant, but the endosperm hardnesses of Zyta, Rysa, Banti, Sakwa, and Mewa varieties were found to be more closely linked with the colour of the central part of the endosperm (r ranging from 0.53 to 0.76), whereas that of durum and Elena wheats were found to be more closely linked with the colour of the whole endosperm (r=0.70 and 0.57 respectively). It was observed that the varieties examined can be divided into three groups differing in the range of changes in hardness as a function of the b* attribute of endosperm colour. For group I (durum and Zyta), the rate of hardness increase was higher than that of group II (Rysa, Banti and Sakwa). The third group (Elena and Mewa) was characterised by the highest slope of hardness versus b*; however, it was well differentiated from group I by its low values for yellow.     

制粉对小麦粉营养品质影响机理研究现状

小麦制粉是利用机械力作用将小麦胚乳与皮层和胚逐步分离后,再将其胚乳研磨成粉的过程。小麦籽粒中营养物质分布不均匀,在制粉过程中,受制粉系统、机械力作用、筛理分级等因素的影响,胚乳出现不同程度的破碎,不同粒度级的小麦粉营养组分含量及分布也存在着一定差异。同时,随着胚乳的破碎,细胞壁破裂、淀粉与蛋白分离,营养组分和酶的作用位点更多的暴露,从而提高营养组分的消化性和生物利用率。本文综述了制粉过程的相关因素对小麦粉营养品质影响机理研究现状,以了解小麦制粉过程中各营养素的变化和损失,为后续制粉过程中充分保留营养素、提高营养素利用率提供参考。     

Wheat endosperm hardness. Part II. Relationships to content and composition of flour lipids

In Part I we analysed hardness and colour of wheat endosperm and stated that these features are quite well correlated among kernels of individual varieties. In order to enhance knowledge of the biochemical basis of endosperm hardness, this study aimed at determining how the content and the composition of free and starch lipids influence it. Wheat samples (used previously in Part I) were milled in a way that reduced the number of non-endosperm particles in flour. Simple linear correlation coefficients between endosperm hardness and its lipid composition indicated that hardness was positively correlated with the content of free glycolipids (r=0.82) and negatively with the content of surface lipids of starch, especially with their non-polar fraction (r=-0.83). The typical feature of harder wheat varieties was a substantially higher content of oleic acid in lipids of the starch surface.     

Proteins in developing sorghum endosperm that may be involved in resistance to grain moulds

The level and type of fungal infection on grains varying in hardness at different stages of development over two seasons has been studied. Hard grains showed less incidence of grain moulds than soft grains during development. Microscopic examination showed more intense deposition of protein bodies in hard than in the soft grains. The presence of fungal hyphae in the endosperm of soft grains and pitted starch granules was clearly visible microscopically. Extracts of immature and mature hard and soft endosperm were inhibitory to Fusarium moniliforme growth. These inhibitors were heat labile and non-dialysable indicating that protein factors may be involved. The activities of inhibitors to serine proteases were comparatively higher in endosperm of hard grains during development. The endosperm of hard grains contained more protein and prolamine than that of soft grains. A role for proteins in resistance of fungal infection in low tannin lines is presented.     

FACTORS INFLUENCING THE HARDNESS (MILLING ENERGY) AND MALTING QUALITY OF BARLEY

The hardness of samples of 41 barley cultivars grown in Australia was determined by measuring milling energy. The milling energy was negatively correlated (r= ?0.49) with the starch and positively correlated (r=0.50) with the β-glucan content. The correlation with protein content was not significant. This suggests that a low starch content and a high β-glucan content may contribute to hardness but other factors may probably also be involved. The extent of modification of these barley samples measured by Calcofluor staining after steeping and 48 h of germination was correlated with the grain hardness (r= ?0.56). Factors contributing to grain hardness may limit the rate of endosperm modification during malting, indicating the value of selecting softer cultivars for malting.     

Wheat (Triticum aestivum L. and T. turgidum L. ssp. durum) Kernel Hardness: I. Current View on the Role of Puroindolines and Polar Lipids

Wheat hardness has major consequences for the entire wheat supply chain from breeders and millers over manufacturers to, finally, consumers of wheat‐based products. Indeed, differences in hardness among Triticum aestivum L. or between T. aestivum L. and T. turgidum L. ssp. durum wheat cultivars determine not only their milling properties, but also the properties of flour or semolina endosperm particles, their preferential use in cereal‐based applications, and the quality of the latter. Although the mechanism causing differences in wheat hardness has been subject of research more than once, it is still not completely understood. It is widely accepted that differences in wheat hardness originate from differences in the interaction between the starch granules and the endosperm protein matrix in the kernel. This interaction seems impacted by the presence of either puroindoline a and/or b, polar lipids on the starch granule surface, or by a combination of both. We focus here on wheat hardness and its relation to the presence of puroindolines and polar lipids. More in particular, the structure, properties, and genetics of puroindolines and their interactions with polar lipids are critically discussed as is their possible role in wheat hardness. We also address future research needs as well as the presence of puroindoline‐type proteins in other cereals.     

Variation in bread-making quality: effects of weather parameters on protein concentration and quality in some Swedish wheat cultivars grown during the period 1975–1996

Two spring and two winter wheat cultivars were investigated for bread volume, grain protein concentration and mixogram index. Data for the weather conditions—mean day temperature per month, precipitation per month, and sun hours per month—were collected for the same period. Relationships between the quality factors were studied as well as relationships between these factors and weather conditions. The bread volumes varied from 910 to 1415 ml, and from 630 to 1067 ml for the spring and winter wheats, respectively. The grain protein concentrations were between 11.1 and 14.9% for the spring wheats, and between 10.6 and 16.7% for the winter wheats. Mixogram indexes varied from 110 to 156, and from 89 to 139, for spring and winter wheats, respectively. A strong correlation was found between the bread-making quality and the grain protein concentration and quality. The grain protein concentration and mixogram index accounted for 19% and 15% of the variation in bread volume, respectively. The climatic variables influenced on bread volume, and grain protein concentration and quality. The temperature, specially during the grain filling period, was the most important weather parameter, explaining 34% of the variation in grain protein concentration and 49% of the variation in mixogram index in spring wheat. The influence of the weather on the quality parameters, were more complex in the winter wheats. © 1998 Society of Chemical Industry.     

Effect of wheat puroindoline alleles on functional properties of starch

Puroindoline a and b (Pina, Pinb) form the molecular basis of bread wheat grain hardness. Varieties with a softer endosperm and a wild genotype, in which both Pina and Pinb were present, seemed to produce less damaged starch flour than hard varieties, where Pin mutations occurred and changed the starch rheological properties. The functional property of starch samples extracted from wheat varieties with different Pin alleles was evaluated. Starch morphology was characterized by scanning electron microscopy and laser light scattering. Thermal properties were evaluated by differential scanning calorimetry. Amylose content, starch damage and rapid visco-analyser (RVA) parameters were also determined. Significant variations (P < 0.05) were identified between different Pin variants for the distribution pattern of starch granule volume, amylose content, starch damage, RVA viscosity breakdown and retrogradation, gelatinisation transition temperatures and enthalpies. Hard genotypes presented higher medium diameter granules and lower enthalpic values. However, the differences detected are more evident among varieties that present both Pina and Pinb, than among those presenting only one of the two (a or b).