Mixing history affects gluten protein recovery, purity, and glutenin re-assembly capacity from optimally developed flour–water batters

Batters, from three wheat cultivars, were mixed up to their maximal consistency (t_peak) at different mixing speeds (N) and flour/water ratios [Auger, F., Morel, M.H., Lefebvre, J., Dewilde, M., Redl, A., 2008. A parametric and microstructural study of the formation of gluten network in mixed flour–water batter. Journal of Cereal Science 48, 349–358]. Gluten and starch were extracted from those batters using a process which included two successive steps: dilution and sieving. In order to reveal the specific influence of the mixing step, a standardized gentle washing and sieving procedure was selected. Mixing the batters at t_peak guaranteed a high and stable gluten protein recovery (ca. 82%) irrespective of mixing conditions. SE-HPLC analysis of protein, from flours and batters sampled at t_peak, demonstrated that mixing led to the almost total breakdown of the unextractable glutenin polymers (ca. 80%), whereas their re-assembly occurred during gluten extraction. The extent of glutenin re-assembly in gluten was influenced by the batter mixing history and was mainly related to the number of mixing rotations (N.t_peak). Gluten protein contents were also found related to N.t_peak. We proposed that the leaching of starch from the batter during gluten extraction was controlled by the elasticity of the protein network, i.e. the gluten content in unextractable glutenin. An innovating scheme relating the glutenin re-assembly capacity to the irreversible thiol protein oxidation is proposed.     

Rheological and mechanical properties of bioplastics based on gluten- and glutenin-rich fractions

The present work aims to investigate the dynamic rheology at small strains and the equibiaxial extensional deformation at large strain of the glycerol plasticized dough of gluten- and glutenin-rich fractions and their mixture as well as the uniaxial tension deformation behavior of the compression molded bioplastics. The influence of glutenin-to-gluten ratio (GGR) on the rheological properties of the glycerol plasticized doughs and the crosslinked bioplastics were investigated. The results showed that the glutenin dough exhibits higher moduli and lower loss factor and equibiaxial deformability in comparison with the gluten dough. Addition of a glutenin-rich fraction to the gluten dough can improve elasticity at small deformation and extensional deformational stress at large deformations but result in reductions in extensibility of the compression molded bioplastics.     

我国冬小麦品种谷蛋白聚合体的分布及其与和面仪参数的关系

利用GMP的丙醇--双缩脲改良测定法,对我国冬麦区124份有代表性的冬小麦品种和品系的谷蛋白聚合体进行了测定,系统探讨了谷蛋白聚合体与和面仪参数的关系.结果表明:(1)我国小麦品种面粉谷蛋白大聚合体(GMP)含量的分布范围在1.70%～6.60%之间,平均含量为3.87%;GMP在面粉蛋白质中所占的比例(GMP/Pr)平均为31.21%;面粉可溶性谷蛋     

小麦谷蛋白聚合体的MS-SDS-PAGE及其与面包烘烤品质的关系

选用品质(微量SDS沉淀值、稳定时间)优劣不同的10个"9311168///81831-1/pernell//京411"的F6品系, 探索多层浓缩胶SDS-PAGE(MS-SDS-PAGE)的实验方法, 初步探讨可溶性谷蛋白的分子量分布状况和不溶性谷蛋白(GMP)与面包烘烤品质的关系. 结果表明, 通过SDS-磷酸缓冲液可将谷蛋白聚合体分成两部分: 分子量较小的SDS-可溶性谷蛋白     

311份小麦品种(系)优质麦谷蛋白亚基组成分析

为明确小麦品种(系)中优质麦谷蛋白亚基组成,筛选优质小麦品种资源,本研究以116份贵州省小麦品种(系)、195份省外小麦品种为供试材料,采用STS分子标记方法,对优质高分子量麦谷蛋白亚基Ax2^*、Bx7^oe、By8和低分子量麦谷蛋白亚基Glu-A3d、Glu-B3g进行分子检测,并利用近红外谷物品质分析仪测定311份材料的蛋白质含量,探讨了其与各个优质亚基间的相关性。结果表明:311份供试材料中,亚基Bx7oe、By8和Glu-B3g的分布频率分别为90%、78.14%和39.87%,优质亚基Ax2*和Glu-A3d分布较少,频率均为2.89%,不同优质麦谷蛋白亚基及组合对小麦蛋白质含量存在显著性影响,亚基Ax2^*和亚基组合7oe+8/A3d/B3g对蛋白质含量的贡献最大。本研究结果为改良小麦面筋质量、准确筛选优质种质资源提供依据。     

小麦谷蛋白聚合体粒度分布与面粉揉面特性关系的研究

 选用在谷蛋白 Glu- 1和 Glu- 3的 5个位点 (除 Glu- A1位点外 )上均带有不同等位基因的小麦品种 Suneca和 Cook的杂交 F4 代群体中谷蛋白各亚基位点均为纯合基因的 60个系 ,测定基因型不同的系间谷蛋白聚合体粒度分布和面粉揉面特性的变异 ,研究小麦谷蛋白聚合体粒度分布与面粉揉面特性的关系。结果表明 ,不同的谷蛋白基因型 ,其谷蛋白聚合体粒度大小相对分布 (即 U PP% )和面团形成时间 (即揉面曲线图峰值的和面时间 ,PTM)均有显著差异。面粉的揉面曲线形状与其 U PP%值密切相关 ,U PP%与 PTM呈极显著正相关 ,与揉面曲线图峰高 ( PHM)呈显著负相关 ;与面粉蛋白质含量 ( FP% )相比 ,U PP%对 PTM和 PHM的影响更大些 ,可作为育种早代品质性状选择的一个指标     

Genetic diversity in Hordeum chilense Roem. et Schult. germplasm collection as determined by endosperm storage proteins

Hordeum chilense Roem. et Schult. shows interesting characteristics for breeding, such as disease or pest resistance and has high variability for endosperm storage proteins, valuable for the improvement of the breadmaking quality of both tritordeum and wheat. Knowledge of the genetic structure and the level of H. chilense genetic diversity within its distribution zone may be important to decide on breeding strategies as well as management procedures. The pattern of genetic variation within and among different regions of the distribution area of H. chilense, was analysed by endosperm storage proteins (gliadin and low-molecular- weight glutenin subunits). Several analyses were performed including AMOVA, direct correlation between phenotypic and geographic distance matrices and spatial genetics differentiation. Most genetic diversity was caused by differences among individuals within a population, although all the analyses performed suggest the existence of a low degree of differentiation within regions. Correlation values between phenotypic and geographic distances were low but significant. The spatial genetics analysis revealed that the average phenotypic distances of each of the spatial distance class were not lower (or higher) than that expected by chance. These results are explained by their neutral behaviour towards a selection of endosperm storage proteins and could be very useful in optimising future sample collecting strategies.     

Milling and baking properties of field grown wheat expressing HMW subunit transgenes

Milling and baking tests were carried out on three transgenic wheat lines and their parental varieties grown in the field at two UK sites. The transgenic and control lines were essentially similar in their milling properties but the subunit 1Ax1 and 1Dx5 transgenes had different effects on breadmaking. The subunit 1Dx5 transgene resulted in a low loaf volume and poor crumb structure when expressed in lines with two or five endogenous HMW subunits, and this was accompanied by a greatly increased elastic modulus of the gel protein fraction. In contrast, the 1Ax1 transgene resulted in improved breadmaking quality and a more modest increase in the gel protein elastic modulus when expressed in the two subunit background. Blending of flour from a line expressing the 1Dx5 transgene with flour from a normal breadmaking wheat variety resulted in decreased breadmaking quality, even at a ratio of 1:9. The difference in the results obtained with the 1Ax1 and 1Dx5 transgenes may relate to the presence of an additional cysteine residue in the protein encoded by the latter, which promotes a more highly cross-linked glutenin network.     

花后干旱和渍水对小麦籽粒HMW-GS及GMP含量的影响

采用SDS-PAGE和切胶比色进行亚基定量，研究花后干旱和渍水对小麦强筋品种豫麦34和弱筋品种扬麦9号籽粒HMW-GS和GMP含量的影响。结果表明，两品种的干旱处理和豫麦34淹水处理在花后10 d籽粒HMW-GS形成，两品种对照和扬麦9号淹水处理在花后15 d籽粒HMW-GS形成，说明花后干旱提早了小麦籽粒HMW-GS的起始形成。干旱促进了小麦籽粒HMW-GS早期积累，但对后期积累不利，使快速积累期缩短，渍水处理更明显缩短籽粒HMW-GS快速积累期。两品种成熟期总HMW-GS和GMP含量表现为对照>干旱>渍水，且豫麦34各处理大于扬麦9号的对应处理。     

小麦高分子量谷蛋白亚基14+15、7+8、1与部分品质性状关系的研究

利用在1B上含有14 15亚基的山农910180—3和在1B上含有7 8亚基的淄麦12进行杂交，在分离后代中得到14 15和7 8亚基的株系，分析了它们的蛋白质含量、干、湿面筋含量、沉降值和面筋指数等5个品质性状。品质性状的方差和相关性分析表明：14 15亚基对小麦加工品质有很大的贡献，好于7 8亚基，14 15亚基对沉降值的贡献比7 8亚基大18％；对14 15亚基、1亚基与面筋指数的关系也进行了探讨，结果表明，虽然14 15、1亚基对沉降值的影响是一致的，但对面筋指数的影响却不相同；在高蛋白质水平上，蛋白质含量和沉降值呈显著负相关；沉降值与面筋指数呈正相关。