小麦湿面筋含量和面筋指数遗传分析

利用7个面筋品质不同的小麦品种(系),按Griffing双列杂交法II配制21个杂交组合,对小麦湿面筋含量和面筋指数进行了遗传分析。在7个亲本中,新麦18的湿面筋含量和面筋指数均较高,一般配合力好,能显著地提高杂种后代的湿面筋含量和面筋指数;周8425B湿面筋含量最高,一般配合力较好,可以较快地提高后代湿面筋含量,但后代面筋指数较差,综合品质不易得到提高。小麦湿面筋含量和面筋指数是由多基因控制的数量性状,不仅受加性和显性效应影响,还存在非等位基因间互作。湿面筋含量的高值受显性基因控制,早代即可表达,容易选择;而面筋指数的高值却受隐性基因控制,早代不宜选择。湿面筋含量狭义遗传力相对较低,而面筋指数狭义遗传力较高,且二者间相关性不强。湿面筋含量和面筋指数具有实验操作简单、方便快捷、需要样品少等优点,可用于指导优质育种和小麦生产。     

土壤质地对冬小麦旗叶可溶性蛋白含量及籽粒干物质积累动态的影响

2003~2005年连续2年在池栽条件下,选用粘、壤、砂土3种土壤质地,以面筋含量高、中、低3个冬小麦品种藁麦8901、豫麦49号和洛麦1号为供试材料,对籽粒灌浆期间小麦旗叶可溶性蛋白含量及籽粒干物质形成与积累动态进行了研究。结果表明:3种冬小麦品种在不同质地土壤条件下,灌浆期旗叶可溶性蛋白含量存在一定差异,总的变化趋势表现为开花后随籽粒灌浆进程,旗叶中的可溶性蛋白含量逐渐降低;3种冬小麦粒重增加趋势基本一致,但不同品种在不同质地土壤条件下种植,粒重及灌浆速率表现不同。面筋含量较高的藁麦8901和较低的洛麦1号,成熟期粒重大小均表现为壤土>粘土>砂土;而面筋含量中等的豫麦49号表现为壤土>砂土>粘土。面筋含量较高的品种灌浆高峰出现较早,且灌浆速率较低;面筋含量较低的品种灌浆高峰出现较晚,但灌浆速率较高。3种小麦品种灌浆期粒重与旗叶可溶性蛋白含量均呈负相关。     

玉米蛋白粉水解多肽对光磷水蜈蚣的生根抑制活性

以木瓜蛋白酶、中性蛋白酶为水解酶,以玉米蛋白粉为底物,制备出不同酶解时间条件下的玉米蛋白水解多肽。用培养皿生物分析法检测不同玉米蛋白水解多肽在不同浓度(0.5 mg/mL、1 mg/mL、2 mg/mL、5 mg/mL)条件下对光磷水蜈蚣(Kyllinga brevitoliavar.leiolepis)种子生根抑制活性。结果表明:①两种蛋白酶不同水解时间制备的玉米蛋白粉水解多肽对光鳞水蜈蚣种子萌发生根均有抑制作用,且随着浓度增高生根抑制活性增强;②木瓜蛋白酶在水解3 h和6 h制得玉米多肽的生根抑制活性明显优于水解9 h和12 h制得的玉米多肽,而中性蛋白酶在不同水解时间水解玉米蛋白粉所得的水解多肽对光磷水蜈蚣的抑制活性无显著性差异;③木瓜蛋白酶制备的玉米多肽比中性蛋白酶制备的玉米多肽生根抑制活性强,并达到极显著性差异水平(P<0.01)。     

酶解谷朊粉对肉仔鸡免疫功能的影响

为了探究酶解谷朊粉对肉仔鸡免疫功能的影响,本试验选用108只肉鸡,随机分为对照组、谷朊粉组和酶解组3个处理组,每组3个重复。对照组饲喂全价基础日粮,谷朊粉组饲喂添有1.2%谷朊粉的日粮,酶解组饲喂添有1.2%谷朊粉酶解液的日粮。结果表明,日粮中添加谷朊粉酶解物后,在21日龄时,酶解组肉仔鸡的胸腺、法氏囊指数较对照组均有显著提高（P〈0.05）,42日龄时,各处理组肉仔鸡的胸腺、法氏囊指数差异均不显著（P〉0.05）,而在脾脏指数方面,无论是21日龄还是42日龄,添加酶解谷朊粉组脾脏指数均呈升高趋势（P〉0.05）。对于整个试验期,胸腺、法氏囊的发育有不同程度的促进作用,其中对早期免疫器官的发育具有显著的改善作用。在肉仔鸡整个生长阶段,日粮中添加谷氨酰胺可提高新城疫HI滴度,还可促进肉鸡外周血T淋巴细胞的分裂增殖,其中以42日龄时酶解组提高最为显著。     

不同质地土壤冬小麦灌浆期籽粒蛋白质和淀粉含量变化动态

对 3个不同面筋含量的冬小麦品种藁麦 890 1 (高 )、豫麦 49号 (中 )、洛麦 1号 (低 )在 3种不同质地土壤 (砂壤、中壤、粘壤 )条件下种植灌浆期籽粒蛋白质、淀粉含量的动态变化进行了研究。结果表明 :面筋含量较高的品种在粘壤条件下蛋白质含量较高 ,而淀粉含量较低 ,砂壤地与之相反 ,中壤地蛋白质含量和淀粉含量处于砂壤和粘壤之间 ;面筋含量中等的品种在中壤条件下蛋白质含量和淀粉含量都较高 ;面筋含量较低的品种在中壤条件下蛋白质含量和淀粉含量较高 ,粘壤次之 ,砂壤条件下二者含量较低 ;灌浆期 3个冬小麦品种籽粒蛋白质含量和淀粉含量呈高度的负相关 ,二者含量动态变化基本上呈相反的趋势。     

Variation in rheological properties of gluten from three biscuit wheat cultivars in relation to nitrogen fertilisation

Rheological properties of gluten from three biscuit wheat cultivars (Triticum aestivum, L., cv. Reaper, Ritmo, Encore) were studied. The cultivars were grown in two seasons (1997–1999) with three different nitrogen levels, and nitrogen fertiliser was applied using three different strategies. Protein and gluten contents were significantly affected by the N level (P<0.001), but inter-cultivar differences were only significant in 1999, when growing conditions were restricted by environmental factors. The viscoelastic properties of gluten were characterised by creep recovery and oscillation testing. The results showed a significant inter-cultivar effect (P<0.001), with an additional effect from the N level (P<0.001). Increasing levels of nitrogen fertiliser increased the viscous properties of gluten, through an increase of maximum strain and recovery strain, and through a decrease of the storage (G′) and loss modulus (G′′), whereas the phase angle, δ, increased. This increase in viscous behaviour is suggested to be attributed to a higher gliadin/glutenin ratio in the gluten. The fertiliser application strategy did not influence the rheological properties significantly. Thus, high N fertiliser application in biscuit wheat cultivation may be beneficial to obtain rheological properties, which are suitable for biscuit making.     

Interaction of water unextractable solids and xylanase with gluten protein: effect of wheat cultivar

A previously proposed explanation for the change in gluten properties on addition of pentosans to doughs was based on data for only one wheat cultivar. Using three wheat cultivars, Scipion, Soissons and Amazon, differing in technological quality from weak to strong we have obtained results that support the previous explanation. In addition to standard techniques for characterizing gluten and glutenin macropolymer (GMP) yield, composition and properties, a new technique (particle size analysis) was applied that provides further detail on GMP particle size distribution. For each of the three wheat cultivars the effect of WUS and xylanase on gluten and GMP yield, composition and properties followed the trend previously observed. However, WUS and xylanase affected gluten yield and properties more strongly for Scipion and Soissons than for Amazon. Amazon flour contains more protein and less pentosans. The analysis of GMP particles demonstrates that the volume surface average particle diameter D_3,2 of GMP particles from Amazon wheat is larger than those from Scipion and Soissons. Amazon has the ability to form larger and stickier particles. These factors may explain why the effects of pentosans and xylanase on gluten yield and properties are smaller for this wheat.     

How gluten properties are affected by pentosans

In the gluten-starch separation process gluten is formed first as a result of breakdown of the gliadin-glutelin structures during mixing followed by their re-agglomeration. To date the effect of pentosans and enzymes have not been studied separately. A simple modification of TNO Glutomatic system enables pentosans, enzymes, and other materials to be added after the mixing step allowing the effect of these additives to be studied separately. Using this technique, we observed that re-aggregation of gluten proteins starts immediately after the first mixing step during the dough dilution phase. Xylanase addition prior to dough mixing can lead to ‘overdose effects’ but these were not observed when xylanase was added later during the re-agglomeration phase. We were able to distinguish between physical and chemical effects of pentosans on gluten formation. The effect of water-extractable pentosans is only partly related to its viscosity, a ferulic acid (FA) related reaction is more important. Pentosans affect the affect the agglomeration by increasing the size of the glutenin macropolymer particles. When the water-extractable pentosan effect is prevented by xylanase or FA addition, aggregation during dilution is more extensive and the glutenin macropolymer has a lower average particle size with a resulting difference in gluten rheology.     

Starch properties, in vitro digestibility and sensory evaluation of fresh egg pasta produced from oat,teff and wheat flour

Specific dietary requirements, e.g. celiac disease, as well as increased consumer demand for products of high nutritional value, makes the production of pasta from alternative cereals interesting. Raw material characterisation showed that the utilisation of oat and teff flour is beneficial as these ingredients contain higher levels of fibre and mineral composition is superior to that of wheat. Starch properties significantly influence pasta quality and therefore damaged starch levels, amylase activity, pasting properties and gelatinisation temperatures of the flours were investigated. Fresh egg pasta based on wheat, oat and teff flour was produced. Sensory properties of oat spaghetti were found to be very close to that of wheat pasta but improvement of smoothness and aroma is necessary, while teff spaghetti showed reduced sensory quality. An in vitro enzymatic digestion was performed using a dialysis system to mimic the behaviour of pasta as eaten and make predictions on the glycemic index (GI). The predicted GI was highest for wheat pasta, followed by teff and oat. Ultra structure was studied using confocal laser scanning microscopy, allowing the visualisation of differences in starch granule size and shape as well as gelatinisation occurring during the cooking process.     

Impact of late-season N fertilisation strategies on the gluten content and composition of high protein wheat grown under humid Mediterranean conditions

The rise in high protein common wheat in humid Mediterranean areas has determined a need to compare specific and effective nitrogen (N) fertilisation protocols in order to increase their end-use value. The aim of the work was to assess the impact of late-season N fertilisation strategies on grain yield and protein content (GPC), gluten fraction composition, and rheological traits. Different applications and types of fertiliser (soil applied ammonium nitrate, soil applied urea, foliar applied urea and a foliar applied commercial fertiliser) were distributed at the same rate (30 kg N ha⁻¹) in a field experiment in NW Italy, during three growing seasons. A control without any late-season N fertilisation was also considered. All the treatments received 130 kg N ha⁻¹ as ammonium nitrate (AN), which was split between tillering and the beginning of the stem elongation growth stages.None of the compared late-season N fertilisations significantly affected canopy greenness and stay green duration during the grain filling period, or the grain yield, test weight, and thousand kernel weight, although the foliar application significantly increased foliage burning (+9.8%). The late application of N consistently increased GPC (+1.1%) and dough strength (W, +21%) in the different growing seasons. The type of fertilisation strategies clearly affected the gluten content and rheological parameters: AN was more effective than urea as a soil top-dressed applied fertiliser in increasing W (+10%), as a result of a higher rise in the GPC content (+0.5%) and extensibility (L, +11%). The foliar application at anthesis, at the same N rate, led to a comparable GPC and W with those of the soil top-dressed granular fertiliser. Only a weak effect of granular urea on y/x type HMW was observed for the gluten composition. Conversely, a notable influence of year was observed (i.e. GS/Glia and y/x type HMW), which in turn resulted in a significant impact on W and P and on the aggregation time and aggregation energy.This study offers a further contribution to the improvement of specific N fertilisation strategies in order to enhance the wheat quality according to its end-use value.