Wx基因对小麦淀粉合成关键酶活性的影响

为研究Wx基因的缺失对小麦淀粉合成关键酶活性的影响,本试验以8个Wx小麦近等基因系为材料,在灌浆期的10、20、30和40 d取籽粒对ADP-葡萄糖焦磷酸化酶(AGPase)、可溶性淀粉合成酶(SSS)、颗粒结合型淀粉合成酶(GBSS)和淀粉分支酶(SBE)活性进行了测定。结果表明:野生型的AGPase、SSS、GBSS和SBE活性在花后所有时期均最高(GBSS花后40 d除外,处于中间水平),而WxABD型4种淀粉合成相关酶活性几乎在整个灌浆期均低于其余基因型,尤其是WxABD型的GBSS活性尽管也呈现先升高后降低、20 d左右达到高峰的趋势,但其升高或降低的幅度很小,其活性相对较为稳定。研究证明小麦Wx基因缺失对淀粉合成关键酶活性影响较大,依次为Wx-D1Wx-A1WxB1;淀粉合成关键酶活性在花后逐渐增加,以花后20 d最大,此后逐渐降低,到40 d达最低值;WxABD型缺失所有Wx基因,淀粉合成酶活性在花后各时期最低,其中GBSS活性远低于其余基因型且在花后各时期变化较小。     

不同颗粒结合型淀粉合成酶Ⅰ亚基组合对小麦淀粉含量及面条品质的影响分析（网络首发、推荐阅读）

控制颗粒结合型淀粉合成酶Ⅰ（Wx蛋白）形成的基因是直链淀粉合成的关键基因,该基因的表达影响直链淀粉含量,进而影响最终加工品质。以含有不同Wx蛋白亚基组合类型的重组自交系（RIL）群体为材料,研究不同组合类型对直支链淀粉含量及面条品质质构的影响。结果表明,群体中共含有8种组合类型,不同Wx蛋白亚基位点缺失对小麦直、支链淀粉含量影响的程度不同。双缺失类型之间直支链淀粉含量都没有显著差异;突变型和其他组合相比达显著差异。Wx蛋白亚基的缺失主要影响干面条断裂强度。在双缺失类型下,组合中存在Wx-B1缺失位点时对面条干面条断裂强度影响较大,不易断裂。单缺失类型下,影响煮熟面条拉伸参数严重程度为Wx-A1≥Wx-B1>Wx-D1;双缺失类型下,Wx-B1和Wx-D1同时缺失时为最优;全缺失时,主要影响煮熟面条的拉伸距离,其次是曲线面积和拉伸力。研究结果为优质专用小麦新品种的培育提供参考。     

双波长法测定小麦及小麦芽中直链、支链淀粉含量

采用双波长法对15种小麦品种的直、支链淀粉的含量进行了测定,并选择淀粉含量及支链/直链比有代表性的6个品种进行制麦试验,研究了小麦制麦芽期间淀粉含量的变化,以期探讨一种简便快捷的测定小麦及麦芽中淀粉含量的方法,并为筛选适合制麦芽小麦品种提供依据.根据碘-直链淀粉和碘-支链淀粉复合物的吸收光谱,选择直链淀粉的测定波长为631 nm和480 nm,支链淀粉的测定波长为554 nm和754 nm,依据回归方程可求出直链和支链淀粉的含量.直链淀粉的浓度在0～30μ/mL,支链淀粉在0～110μg/mL范围内符合比耳定律.制麦前后总淀粉降解程度与原小麦中支链/直链淀粉存在正相关性(P<0.1),相关系数r=0.802.     

双波长分光光度法测定木薯块根淀粉含量的动态变化

以双波长分光光度法测定SC201、SC205、GR891和GR911共4个木薯品种生育期块根中直链淀粉与支链淀粉含量的动态变化.结果表明,4个木薯品种块根直链淀粉的含量是随生育期的延长而逐渐增加的,而支链淀粉的含量却缓慢下降,支链淀粉/直链淀粉的比例呈现下降趋势,到12月份4个品种的这一比例已接近相同;以鲜重计的总淀粉含量,4个品种均呈逐渐增加的趋势;而以干重计的总淀粉含量的变化则4个品种表现不一致.研究初步揭示了木薯块根直链淀粉、支链淀粉和总淀粉含量的积累规律.     

不同Wx蛋白重组类型对普通小麦直链淀粉含量及RVA参数的影响

小麦Wx蛋白是控制直链淀粉合成的关键蛋白,与淀粉品质的关系密切.为了明确Wx蛋白的重组对小麦直链淀粉含量及RVA参数等淀粉品质指标的影响,本研究选择非糯与糯性小麦组配杂交组合,利用SDS-PAGE检测了杂交后代的Wx蛋白重组类型,并测定了不同重组类型的直链淀粉含量、膨胀势和RVA参数等淀粉品质指标,结果表明Wx蛋白全缺失型的直链淀粉含量显著低于野生型、单缺失型和双缺失型;膨胀势检测中,Wx蛋白全缺失型的均值较其他重组类型低,但多重比较结果表明不同Wx蛋白重组类型对膨胀势的影响差异不大;不同RVA参数中,Wx蛋白重组类型的作用大小不同,在峰值黏度指标中,全缺失型的影响最大,野生型、单缺失型、双缺失型间的作用相近;低谷黏度和最终黏度指标中,野生型与全缺失型的影响差异较大,其他重组类型的作用相近;在稀懈值、反弹值、峰值时间、糊化温度四个指标中,Wx蛋白重组类型间的作用没有太大差异.     

不同生长发育阶段的谷蠹对小麦淀粉含量及其糊化特性的影响

为了探讨被不同生长发育阶段谷蠹蛀蚀的小麦,其淀粉含量和全麦粉糊化特性的变化规律,选用河南产储藏1年的普通小麦为材料,设定谷蠹在最适生长发育条件下(32℃±1℃,75%±1%RH)对小麦发生侵害,研究在谷蠹卵期、幼虫期、蛹期和成虫期,被侵害后的小麦直链淀粉含量、支链淀粉含量、总淀粉含量及其全麦粉糊化特性的变化,并对其进行相关性和差异性分析。结果表明:小麦被不同虫期的谷蠹蛀蚀后,其中总淀粉、直链淀粉、支链淀粉含量与谷蠹的生长发育期呈极显著负相关;在谷蠹整个生长发育阶段,被幼虫期和成虫期谷蠹侵害后的小麦,其糊化特性指标变化差异极显著。在谷蠹生长发育各阶段,受侵害的小麦,其淀粉含量整体呈现降低趋势,并且在到达成虫期的整个侵害过程中,小麦直链淀粉含量下降的幅度明显高于支链淀粉含量下降的幅度,支链/直链逐渐升高;峰值黏度和低谷黏度呈先升高后降低的变化趋势,衰减值、最终黏度和回升值都逐渐升高,糊化时间基本不变。     

复合有机肥对烤烟淀粉生物合成的影响

为探讨复合有机肥(生物炭占30%,草炭占70%)对烤烟烟叶淀粉合成代谢途径的影响,采用田间试验方法,比较不同施用量下烤烟云烟87叶片超微结构差异、淀粉积累规律以及淀粉合成关键酶基因的表达规律。结果表明:添加复合有机肥有利于叶片细胞中淀粉粒的积累,随着施用量的增加,淀粉粒数目增多、体积变大;总淀粉和支链淀粉含量相应增加,直链淀粉含量反而减少,淀粉组分显著改变;淀粉合成关键酶基因的表达变化与淀粉含量变化一致,颗粒结合型淀粉合成酶基因(GBSS1)的表达随复合有机肥的施用量增加而减弱,可溶性淀粉合成酶基因(SS1)的表达随复合有机肥的施用量增加而增强。由此可见复合有机肥可增加淀粉的积累并改变淀粉组分。     

用Logistic方程模拟稻米淀粉组分的积累特性

选用直链淀粉含量不同等级的粳稻、籼稻、糯稻为材料,分析测定了不同灌浆期稻米总淀粉、直链淀粉、支链淀粉的积累动态特性,并用Logistic方程进行了模拟分析.结果表明:灌浆过程中,6个品种淀粉含量变化趋势一致,均呈“S”型曲线变化;不同品种淀粉组分积累速率高峰出现的时间不同;稻米直链淀粉含量存在显著的品种间差异,且差异从灌浆之初就开始,其中七山占含量最高,沈农576含量最低;Logistic方程能很好地模拟淀粉组分的积累过程.     

小麦胚乳中蛋白质、淀粉组分分布及各性状关系的研究

以小麦品种为9023的各系统面粉样品为试验材料,测定各样品蛋白质及组分含量、湿面筋含量、面筋指数、淀粉及其组分含量,研究小麦胚乳中蛋白质与淀粉及组分分布情况,并对蛋白质和淀粉及各性状间的关系进行初步研究.结果表明:小麦胚乳由内向外,蛋白质含量及球蛋白、醇溶蛋白和谷蛋白含量呈现递增的分布趋势,而淀粉和直链淀粉含量则逐渐减小;球蛋白、醇溶蛋白和谷蛋白含量两两呈现显著或极显著正相关,且与粗蛋白含量显著正相关;湿面筋含量与蛋白质含量、醇溶蛋白和麦谷蛋白含量均呈现极显著正相关关系;直链淀粉含量与总淀粉含量显著正相关,与支链淀粉含量负相关;直链淀粉含量与粗蛋白含量、球蛋白和醇溶蛋白含量均呈显著负相关,支链淀粉含量与谷蛋白含量、湿面筋含量显著正相关.     

制麦过程中小麦淀粉含量及淀粉酶活力变化研究

以 6种小麦为试材 ,对制麦前后小麦直链、支链淀粉含量以及发芽过程中的α、β -淀粉酶活力的动态变化进行了研究 ;对成品麦芽中淀粉酶活、淀粉含量及成品麦芽特性之间的关系进行了分析。制麦前后各品种小麦支链、直链淀粉含量均下降 ,总淀粉降解程度与原小麦中支链、直链淀粉比存在正相关性 (P <0 .1)。成品麦芽中α、β -淀粉酶活与品种有关。成品麦芽糖化力与麦芽中淀粉酶活存在显著 (P <0 .0 5 )正相关性 ;成品麦芽糖化时间与麦芽淀粉含量存在极显著 (P <0 .0 1)正相关性。筛选出豫麦 5 0、SP2 0 2 7、pH97194 2为较好的制小麦麦芽品种     

Chain‐length Distribution Profiles of Amylopectin Isolated from Endosperm Starch of Waxy and Low‐amylose Bread Wheat (Triticum aestivum L.) Lines with Common Genetic Background

Large A‐type endosperm starch granules were isolated from near‐isogenic waxy and non‐waxy lines and low‐amylose mutant lines of bread wheat with a common genetic background. The amylose contents of A‐type starch ranged from 2.6% to 23.6%. Amylopectin was isolated by concanavalin A (Con A) precipitation from the isolated starch. The λ_max (range: 532‐538 nm) and blue values at 680 nm (range: 0.026‐0.037) of the iodine‐amylopectin complex were not significantly different among the isolated amylopectins, indicating that amylopectins from non‐waxy and low‐amylose lines did not contain such long chains as amylose or extra‐long chains of amylopectin affecting iodine complex properties. Chain‐length distribution profiles measured by both high‐performance size‐exclusion chromatography (HPSEC) and high‐performance anion‐exchange chromatography (HPAEC) showed that the amylopectin structures of these lines were indistinguishable from each other. Extra‐long chains were not detected in the amylopectins by HPSEC measurement. The side‐chains measured by HPAEC were classified into four groups according to their degree of polymerization (DP), and the proportion of each group were in the following ranges: DP 6‐12, 26.5‐27.5%; DP 13‐24, 43.6‐44.1%; DP 25‐36, 13.6‐14.2%, and DP 37‐60, 11.0‐11.7%. The alleles on the Wx‐D1 locus, i.e., Wx‐D1a, Wx‐D1d, Wx‐D1f, and Wx‐D1g, responsible for granule‐bound starch synthase (GBSS I) biosynthesis had no influence on the properties of iodine‐amylopectin complex and the chain‐length distribution profiles of amylopectin.     

Effects of Wheat Starch Contents on Malt Qualities

The relationships between wheat starch content and wheat malt qualities were studied in the present work. Six wheat varieties that were typical in starch, protein content and amylopectin/amylose ratio were selected from 12 wheat varieties and germinated under the same conditions. The decreased degree of total starch content after malting had a positive correlation (r = 0.8020, P < 0.1) with the amylopectin/amylose ratio of the raw wheat. Extracts of wheat malts were influenced by starch content and the amylopectin/amylose ratio of the raw wheat. When the amylopectin/amylose ratio was in the range 3.65:1?3.93:1, extracts of the malts had significant positive correlation (r = 0.967, P = 0.002) with the starch content of the raw wheat. In this investigation a suitable amylopectin/amylose ratio (3.65:1 to 3.93:1), a high starch content and a low protein content were the characteristics of a wheat variety suitable for malting.     

不同板栗品种(系)抗性淀粉综合评价

对72个板栗品种(系)栗仁中总淀粉、支链淀粉、直链淀粉、抗性淀粉、以及含水量等重要性状分析的测定,为不同板栗品种(系)的利用提供参考。结果表明,不同板栗品种(系)大小、色泽、形状不同;板栗品种(系)中总淀粉的质量分数在51.33%以上,质量分数最高为‘燕秋’,高达71.21%,质量分数最低的是‘波叶-8’,为51.33%;直链淀粉中含量最高的是‘燕秋’,质量分数为18.56%,最低的是‘大兰口’,质量分数为2.43%;支链淀粉含量最高的是‘金丰’,质量分数为58.35%,最低的是‘小官10’,质量分数为35.2%。板栗中含有较高的抗性淀粉。对不同板栗品种(系)中抗性淀粉进行综合评价,抗性淀粉含量最高的品种是‘燕秋’,质量分数为22.2%;最低的是‘徐玉明道’,质量分数为3.44%。通过对不同板栗品种(系)的淀粉进行相关性分析,表明板栗栗仁中直链淀粉与支链淀粉呈极显著负相关,支链淀粉与总淀粉呈极显著正相关,抗性淀粉与直链淀粉呈显著正相关。     

Amylose content and starch properties in emmer and durum wheat lines with different waxy proteins composition

BACKGROUND: Emmer wheat is a neglected crop that can be used in the breeding of modern durum wheat for quality. One important aspect of this quality is the starch composition, which is related to the waxy proteins. A collection of emmer wheat was analysed previously for waxy protein composition, and two new Wx‐B1 alleles were found by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and DNA sequencing analysis. It is necessary to analyse the effect of these alleles in starch properties and compare them to durum wheat ones. RESULTS: In the current study, emmer lines carrying three different Wx‐B1 alleles (Wx‐B1b, ‐B1g, ‐B1c*), including one with the null allele (Wx‐B1b), together with durum cultivars Langdon (Wx‐B1a) and Mexicali (Wx‐B1c′), were analysed for amylose content. Differences were detected between both species, and the line lacking Wx‐B1 protein showed a remarkably low amylose content. In addition, data from blue value, swelling power and Rapid Visco Analyzer also suggested that there were differences in starch properties among the different Wx‐B1 alleles. CONCLUSION: The present study suggests that the amylose content in emmer (Wx‐B1g) and durum (Wx‐B1a) standard materials is not the same; therefore some starch properties are different between the two species. The variation found could be used to enlarge the gene pool of durum wheat and design new materials with desirable amylose content. Copyright © 2011 Society of Chemical Industry     

Waxy and high-amylose wheat starches and flours—characteristics,functionality and application

Starch is a predominant component of wheat grain. It plays an important role in appearance, structure and quality of food products. Starch consists of two kinds of glucose polymers (amylose and amylopectin) with the ratio of amylose/amylopectin ranging between 25–28 and 72–75%, respectively. The isoforms of granule-bound starch synthase (GBSS) are responsible for the biosynthesis of amylose fraction, whereas amylopectin synthesis is more complicated with concerted activities of the soluble starch synthase together with branching and de-branching enzymes. Recently, waxy (amylose-free) and high-amylose wheats produced through the development of new physicochemical and biological techniques provide the unique starch functional properties. The starches of these wheats have the specific structures and unique characteristics that are believed to enhance the quality of food products. In this review, we will focus on recent advances in the studies of the characteristics of waxy and high-amylose wheat flours and starches and their application for food processing. In addition, we also propose further research ideas for clearer understanding of their characteristics and for their effective utilization.     

Carbohydrate composition of developing grains of the high-lysine barley mutant (notch-2) and its parent (NP 113)

Barley variety NP 113 had higher accumulations of dry matter (DM) and starch than its high-lysine mutant, Notch-2, during grain development. Protein, amylose and amylopectin content per grain were lower in Notch-2 than NP 113. Reducing sugars, free glucose, total fructose and non-reducing sugars were 1.57–3.15-fold in Notch-2 grain as compared with NP 113 grain. DM, protein, starch, amylose and amylopectin per grain increased during grain development. Soluble sugar contents per grain were maximum at 24 days after anthesis. Lower DM accumulation in the Notch-2 mutant as compared with its parent, NP 113, is due to lower starch deposition. Further, the limitation of starch synthesis in the Notch-2 mutant is not due to any limitation in the supply of soluble sugar precursors.     

6种不同种类直支链淀粉相互混合对其回生的影响

目的 研究6种不同种类直支链淀粉相互混合对其回生的影响。方法 将玉米淀粉、甘薯淀粉、木薯淀粉、马铃薯淀粉、糯米淀粉、小麦淀粉等6种不同种类直支链淀粉分离出来, 然后两两混合, 研究不同直支链混合对其回生率的影响。 结果 马铃薯支链淀粉与甘薯支链淀粉以2:8(m:m)混合回生率最低, 为60.0%, 玉米支链淀粉与木薯支链淀粉以8:2(m:m)混合回生率最低为52.6%, 小麦支链淀粉与糯米支链淀粉以8:2(m:m)混合回生率最低为51.2%, 甘薯支链淀粉与小麦支链淀粉以1:1(m:m)混合回生率最低为53.7%。木薯支链淀粉与小麦直链淀粉以1:1(m:m)混合时所得淀粉回生率最大, 达到了92.0%, 混合淀粉回生后X射线晶型为B型。结论 不同种类直支链淀粉混合对其回生率影响很大, 食品加工中尽量不要混合使用木薯支链淀粉与小麦直链淀粉。     

小麦淀粉特性与面包烘烤品质的相关性

利用国内外40个面包小麦品种(系)进行了淀粉性状与面包烘烤品质性状的相关性分析，比较了国内外小麦在加工品质和淀粉性状的差异。结果表明，直链淀粉含量与面包品质性状(Zeleny沉淀值、面团形成时间和稳定时间)呈极显著负相关；淀粉总量与面包品质性状呈负相关，但相关不显著；面粉膨胀势与面包品质性状呈极显著正相关。国内外小麦品种(系)相比，Zeleny沉淀值、面团形成时间和稳定时间等性状差异较大；在淀粉性状和面包品质性状上，国外小麦品种(系)明显优于国内材料。讨论认为，蛋白质和淀粉对小麦的面包烘烤品质都有一定的影响。直链淀粉含量、支链淀粉含量和膨胀势可作为小麦品质育种亲本选配、后代选择的指标。改良我国小麦淀粉的主要目标是降低直链淀粉含量。