水氮对冬小麦花后籽粒淀粉含量及产量的影响

为进一步探索水分和氮肥对小麦淀粉含量和产量的影响,以冬小麦品种矮抗58为材料,在小麦全生育期不灌水(W0)和拔节期灌水(W1)两种水分条件下,分析了不同施氮处理间(0、180、240和300kg·hm 2,分别用N0、N1、N2、N3表示)冬小麦花后籽粒淀粉含量和产量的差异.结果表明,N2处理获得较高小麦籽粒产量、支链淀粉和总淀粉含量及较低直/支比,不施氮或施氮过多均不利高产和籽粒淀粉积累.与W0相比,W1处理有利于小麦籽粒产量提高及支链淀粉和总淀粉积累.水、氮互作对小麦籽粒产量和淀粉含量影响明显.在8个处理中,以W1N2处理对提高小麦籽粒产量和改善籽粒淀粉品质有利,为比较理想的水氮运筹方式.     

追氮时期对两种筋型小麦淀粉糊化特性的影响

大田条件下,选用2个有代表性的强、弱筋型冬小麦品种,研究追肥时期对小麦淀粉糊化特性的影响。结果表明：除糊化时间外,其他性状变异系数均大于10％,而且两种筋型品种之间淀粉糊化特性的变异幅度有较大差异。强筋型品种豫麦34号的淀粉糊化特性值均高于弱筋型品种豫麦50号。随追肥时期变化,两种筋型品种的变化规律不同,且均以拔节期追肥表现较优,因此,拔节期是淀粉糊化特性的较佳施肥时期。     

Impact of native form oat β-glucan on starch digestion and postprandial glycemia

Whole grain oats, as a rich source of β-glucan, have been shown beneficial to glycemic control. In the current study, the impact of native form β-glucan in oat grains (NFO-glucan) on starch digestion and postprandial glycemia was investigated. The dry-milling prepared NFO-glucan sample was enriched with native form β-glucan (15.6%), and an in vitro starch digestion assay of NFO-glucan (0.5% starch equivalent) showed a significant decrease of starch digestion rate compared to oat starch (0.5%, w/v). However, pretreatment by either β-glucanase or pepsin significantly increased the starch digestion. Consistently, an in vivo examination on the postprandial glycemia of the cooked NFO-glucan sample using a mouse model displayed a significant decrease of postprandial glycemia compared to gelatinized oat starch. Further experiment on the pasting property of NFO-glucan sample by a rapid visco-analyser demonstrated both β-glucan and protein affected its viscosity profiles. Scanning Electronic Microscope (SEM) observation revealed a network-like native structure of β-glucan that might encapsulate protein and starch to reduce the enzyme accessibility and so the digestion of starch. Novel food processing technologies to maintain the native form of β-glucan in oat grains might be a better way to modulate the postprandial glycemia of oat-based whole grain foods.     

玉米粉淀粉含量近红外模型建立与优化

以230份玉米自交系为样本，采用旋光法与一阶导数及去一条直线的光谱预处理法，构建玉米粉样淀粉含量的近红外分析（NIRS）模型。研究标明，该模型可显著提高子粒淀粉含量预测的准确性。该模型的定标标准偏差（RMSEE）、交叉验证标准偏差（RMSECV）、外部验证标准偏差（RMSEP）、定标相关系数（R_cal²）、交叉验证相关系数（R_cv²）、外部验证相关系数（R_cv²）分别为0.609、0.722、0.738、0.909、0.864和0.854。建立的玉米粉样NIRS模型可将预测值与化学值偏差控制在1.7%内，能够准确定量分析玉米子粒淀粉含量，应用于育种材料早期筛选及群体水平粗淀粉分析。     

驳枝和施氮对早花烤烟成熟期水溶性总糖和淀粉含量的影响

在大田条件下,研究驳枝和追施氮肥对早花烤烟成熟期叶片中水溶性总糖和淀粉含量的影响。结果表明：高施氮量抑制烟草叶片的水溶性总糖和淀粉积累,然而低氮促进了中部叶水溶性总糖和淀粉积累。     

Seasonal and Diurnal Variation in Water-Soluble Carbohydrate Concentrations of Repeatedly Defoliated Red and White Clovers in Central Kentucky

Nonstructural carbohydrates of pasture plants, comprising water-soluble carbohydrates (WSCs) and starch, may contribute to excessive consumption of rapidly fermentable carbohydrates by grazing horses. Seasonal and diurnal variation in WSCs were studied in red (Trifolium pratense L.) and white clovers (Trifolium repens L.) subjected to a typical management regime of rotationally grazed horse pastures. Two red and two white clover cultivars from monoculture plots were harvested after 4 weeks of growth from April to October of 2015, in the morning and afternoon of each harvest date. Water-soluble carbohydrates were quantified for each harvest, and starch was quantified for two harvests. Mean monthly WSC concentrations ranged from 80 to 99 mg/g (freeze-dried weight basis), whereas mean starch concentrations were 31 and 40 mg/g. In September, white clover had 14% more WSCs than red clover (P < .0001). Water-soluble carbohydrate concentrations were 10% higher in the afternoon than in the morning (P < .0001). Starch concentrations were 290% higher in the afternoon than in the morning (P < .0001), and nonstructural carbohydrate concentrations in the afternoon averaged 150 mg/g. Further studies are needed to determine whether the mixed grass-legume pastures of central Kentucky accumulate enough nonstructural carbohydrates to present risk factors for equine metabolic or digestive dysfunction.     

Dough rheological properties and noodle-making performance of non-waxy and waxy whole-wheat flour blends

Dough rheological properties and noodle-making performance of non-waxy whole-wheat flour (WWF) with partial- or full-waxy (PW- or FW-) WWF substitution were studied. The substitution levels were 0, 250, 500, 750, and 1000 g/kg, respectively. FW-WWF reduced the peak viscosity and pasting temperature of WWF blends as its substitution level was increased due to its higher proportions of B-type starch granules and short amylopectin chains, while PW-WWF increased peak viscosity with the increasing substitution level because of its higher amylopectin content. As demonstrated by farinograph and rheometer measurements, FW-WWF interfered with gluten development because of the increased competition for water by arabinoxylans and amylopectin; however, PW-WWF enhanced dough strength due primarily to its increased protein content. Consequently, FW-WWF showed a detrimental effect on cooked noodle texture as the cooked noodle hardness was reduced by 50% at the 1000 g/kg substitution level. In contrast, PW-WWF enhanced noodle integrity and elasticity by increasing cooked noodle cohesiveness and resilience by 10.1% and 14.8%, respectively, at the 1000 g/kg substitution level. The results suggest that with waxy WWF substitution, the changes in starch composition, arabinoxylans, and protein content could modify the interactions among flour components and influence the quality characteristics of noodle products.     

Supplementing white maize masa with anthocyanins: Effects on masa rheology and on the in vitro digestibility and hardness of tortillas

The aim of this work was to supplement masa made from nixtamalized white maize flour (NWMF) with anthocyanins (0.0, 0.03, 0.06 and 0.12 g/100 g of masa), and to evaluate the effects on the rheological properties of the masa and on color, staling, in vitro digestibility, and hardness of tortillas. Tortilla baking reduced the content of anthocyanins by about 10%. The color parameters of the tortillas added with anthocyanins was similar to that of tortillas made with blue maize. Attenuated total reflection ATR-FTIR spectra showed that the 1022/1047 peak ratio increased, indicative that retrogradation increased with storage time, but the ratio was significantly lower for tortillas with added anthocyanins than without them, and lower for higher anthocyanins concentration. Freshly made tortillas added with anthocyanins exhibited lower ready digestible (about 35%) and slowly digestible (about 20%), but higher resistant (about 45%) starch fractions. Tortillas with 0.12 g of anthocyanins showed significantly lower hardness than the control tortillas (without added anthocyanins). Both previous mentioned effects can be associated with retrogradation, which on turn could be linked to anthocyanins-starch complexes and inhibition of amylolytic enzymes.     

不同淀粉来源对生长猪回肠食糜中微生物氮和氨基酸含量的影响

本试验旨在研究淀粉消化性能的差异对生长猪回肠食糜中微生物氮和氨基酸含量的影响.试验采用4×4拉丁方设计,选择4头回肠末端安装有简单T瘘管的杜×长×大三元杂交公猪进行消化代谢试验.结果显示,淀粉来源不同其回肠末端消化率存在差异,在生长猪的回肠末端抗性淀粉有83.07%被消化;糯米淀粉被100%消化,玉米和糙米淀粉介于二者之同,分别有97.63%和96.41%被消化;回肠食糜中氮的流量以采食抗性淀粉日粮组最高(为每千克干物质采食量7.44 g),而食糜氮中微生物氮所占比例以采食糯米组最高(为72.8%);各组回肠食糜氨基酸流量中微生物氨基酸所占比率变化范围为25.43%(玉米组)～45.09%(抗性淀粉组),其中抗性淀粉组Asp、Glu、Ser和Lys的比率明显高于玉米组(P<0.05),但Tyr却低于玉米组(P<0.05);糙米组Arg显著高于抗性淀粉组,而Ala和Leu却比抗性淀粉组低(P<0.05);糯米组Ala和Leu也明显较抗性淀粉组低.     

大黍的大小孢子发生,雌雄配子体发育及其淀粉动态

通过石蜡切片,在光学显微镜下系统观察了大黍有性生殖过程中大小孢子发生、雌雄配子体发育及其淀粉动态。大黍花药壁由表皮、药室内壁、中层和绒毡层４层细胞组成。在花药发育过程中,表皮细胞始终积累大、小不等的圆球状内含物,该内含物经ＰＡＳ、苏木精分别染色均呈负反应。表皮细胞外壁在花粉成熟时期略有增厚,且具小刺状突起。绒毡层细胞属腺质型。小孢子母细胞在减数分裂过程中胞质分裂属连续型。成熟花粉粒富含较大颗粒的淀