Influence of konjac glucomannan on thermal and microscopic properties of frozen wheat gluten,glutenin and gliadin

The effects of different konjac glucomannan (KGM) concentrations (0.5%, 1.5%, 2.5%, 3.5%, 4.5%, w/w) on the thermal and microscopic properties of the frozen wheat gluten, glutenin and gliadin were investigated in this study. KGM exerted a positive effect on the denaturation temperature and denaturation enthalpy of frozen gluten and gliadin, while KGM decreased those of frozen glutenin. Such effects induced by KGM were resulted from the interaction between KGM and frozen wheat gluten, glutenin and gliadin. The underlying mechanism was discussed from the perspective of protein structure. Specifically, the addition of KGM increased the α-helix structure of frozen gluten and gliadin, while decreased the α-helix of frozen glutenin. Furthermore, β-turn of frozen gluten and gliadin presented a decreasing trend with increasing amount of KGM. Scanning electron microscopy confirmed that there was stronger interaction between wheat protein and KGM. These results provide fundamental knowledge for better application of KGM in frozen protein-based foods.     

发酵时间对馒头品质及面筋蛋白结构的影响

利用体积仪、质构仪和傅里叶变换红外光谱分别测定馒头比容、质构特性与面筋蛋白二级结构,探究发酵时间对馒头品质及面筋蛋白结构的影响。结果表明：馒头中醇溶蛋白与麦谷蛋白中β-折叠含量均为最高。随着发酵时间的不断延长,醇溶蛋白中β-折叠、α-螺旋相对含量无显著性变化,无规则卷曲逐渐减少,而β-转角则逐渐增加;羟基吸收带逐渐增强,醇溶蛋白的水合作用增强。麦谷蛋白中α-螺旋与无规则卷曲相对含量变化不大,β-折叠相对含量先上升后下降,而β-转角相对含量则是先下降后上升;羟基带强度逐渐减弱;当发酵时间延长到80?min时,麦谷蛋白红外光谱位于1?082?cm－1与1?155?cm－1处的峰消失,可能是蛋白质环状结构的C—C振动减弱。     

高温高湿处理对小麦中蛋白质性质的影响

目的：探索高温高湿工艺对小麦及其制品蛋白质性质的影响。方法：分析了经高温高湿工艺处理后小麦粉及其制品的面筋蛋白、麦谷蛋白及麦醇溶蛋白的理化性质、分子性质和超微结构。结果：小麦粉和挂面中蛋白质的水溶性随处理时间的延长而降低;挂面面筋蛋白的持水力优于小麦粉,其中麦谷蛋白的持水能力占主要作用;随着处理时间的延长,小麦蛋白质中相对分子量较大的麦谷蛋白含量增多,而分子量较小的麦醇溶蛋白含量减少。SEM分析发现,热变性使谷蛋白由原来的膜状结构逐渐变成多孔结构,此结构使面筋网络中的孔隙变大,孔隙变大可以更好地包裹淀粉颗粒。结论：高温高湿处理工艺对小麦和面条中的蛋白质性质影响具有差异。小麦粉中的蛋白质持水能力经处理后基本没有变化,而水溶能力则呈下降趋势;面条经高温高湿处理后持水力与水溶力均提高。     

Effects of catechins on the polymerisation behaviour,conformation and viscoelasticity of wheat gluten

The effects of catechins on the structural properties of wheat gluten were investigated in terms of their polymerisation behaviour, conformation and viscoelasticity. Depolymerisation of glutenin macropolymers was analysed by size-exclusion high-performance liquid chromatography (SE-HPLC) of gluten with catechins, revealing major variation in sulfhydryl (SH) content. Compared with controls, the SH content of catechin-enhanced gluten was significantly increased due to breakage of disulphide (SS) bonds. Reversed-phase HPLC revealed that catechins had minimal effect on subunit distribution of gliadin and glutenin. Fourier transform infrared (FTIR) spectroscopy showed that catechins induced the transformation of α-helices to β-sheets, β-turns and antiparallel β-sheets. Rearrangement of secondary structure when supplemented with catechins might be a consequence of altered non-covalent interactions. Catechins increased tan δ, indicating enhanced gluten fluid properties. These results imply that catechins might weaken the network structure of gluten and change the rheological properties by inhibiting SS cross-linkage formation and influencing non-covalent bonds.     

Effects of japonica rice flour on the mesoscopic and microscopic properties of wheat dough protein

The aim of this study was to study the effects of twelve varieties of japonica rice flour on the gluten protein composition and structure of wheat dough. Experimental results indicated that the addition of japonica rice flour significantly decreased the α-helix structure in the gluten protein sample, but increased the random coil content, indicating that the protein secondary structure became more disordered. The ratio of α-helix/β-sheet structures in the dough supplemented with different varieties of japonica rice flour was decreased, contributing to improved dough stability. Increasing the proportion of japonica rice flour from 10% to 40% significantly decreased the sulfhydryl content of the mixed flour dough. However, the total sulfhydryl content was only positively correlated with the amount of Longdao 19 japonica rice flour, reaching a maximum of 25.34 mol g⁻¹ at 40% japonica rice flour. The gluten structure of mixed flour dough typically forms a porous three-dimensional network, with the Longdao 19, 20, 23 and 25, Longjing 31 and Mudanjiang 31 japonica rice flours leading to improved gluten protein networks. In summary, the supplementation of standard wheat flour with japonica rice flour can alter dough properties and gluten structure.     

不同面筋蛋白组分对小麦淀粉消化特性的影响机理

分别将面筋蛋白、谷蛋白及醇溶蛋白与淀粉按一定质量比（14∶86）混合,运用流变仪、热重分析仪及激光共聚焦显微镜等手段分析不同面筋蛋白组分与淀粉/α-淀粉酶之间的相互作用,以明确面筋蛋白及其不同组分对淀粉消化特性的影响及潜在机理。结果表明：与纯小麦淀粉相比,添加面筋蛋白、谷蛋白及醇溶蛋白使酶解120 min的淀粉消化率分别下降了39.93%、49.48%及26.61%。淀粉与不同面筋蛋白组分之间通过氢键相互作用形成了更稳定的复合物,提高了样品的热稳定性。与面筋蛋白和醇溶蛋白相比,添加谷蛋白在淀粉基质周围形成了更加致密的物理性屏障,更大程度地抑制了酶对淀粉的水解。此外,谷蛋白对α-淀粉酶的抑制率最高（约79%）,激光共聚焦观察到的结果也证实了谷蛋白和α-淀粉酶之间的结合程度更高。研究结果有助于丰富典型蛋白质组分调控食品体系中淀粉消化的机理,为低血糖指数食品的开发提供一定理论指导。     

谷朊粉应用概述

本文对谷朊粉的研究历史，组成和应用进行了综述。较全面的概述了谷朊粉中麦醇溶蛋白、麦谷蛋白的结构和性质，介绍了谷朊粉在工业和非工业领域的应用，提出了谷朊粉研究的方向，同时展望了谷朊粉在工业领域的发展前景。     

面筋蛋白与面条品质关系研究

通过分离添加方法研究面筋蛋白、麦谷蛋白、麦醇溶蛋白对面条质构品质影响。结果表明:添加不同量面筋蛋白、麦谷蛋白后,面条硬度、咀嚼性、粘合性增大,而添加麦醇溶蛋白却减小;麦醇溶蛋白赋予面条粘附性;麦谷蛋白能增强熟面条内部强度即耐煮性;面筋蛋白对拉伸特性影响最大。     

小麦面筋蛋白组成、结构和功能特性

小麦面筋蛋白(俗称谷朊粉)主要由麦醇溶蛋白和麦谷蛋白组成,其蛋白组成和结构是影响小麦面团特性和烘焙品质重要因素。该文对小麦面筋蛋白组成、结构进行综述,以更清楚了解其结构对功能性影响。     

陕西省小麦品种资源加工品质性状及利用研究

通过对250份小麦材料的品质分析，摸清了陕西省小麦品种资源的籽粒品质、蛋白质品质、面团流变学特性和蒸煮品质特性等品质状况，提出了利用的途径。结果表明，陕西省小麦品种资源材料的面筋强度以中筋偏弱为主，优质强筋小麦和弱筋小麦材料较少。本省小麦品质改良应重点利用优质硬麦和优质软麦资源材料，改造不软不硬的中间类型。面粉加工企业则应合理利用有限的优质小麦，通过与中筋小麦混配生产优质小麦粉。     

几种酶制剂对面粉品质特性影响的研究

研究了多种酶制剂对面粉品质特性的影响,并对其作用机理进行初步分析,结果表明:葡萄糖氧化、酶脂肪酶F、脂肪酶S使得静态抽提麦胶蛋白、酸溶性麦谷蛋白和游离巯基含量和面皮的粘着力都有不同程度的减小,面筋交联度、二硫键含量和面皮的硬度、弹性、凝胶性、咀嚼性、回复性增加,但总巯基含量基本不变;木聚糖酶则增加了硬度、凝胶性和咀嚼性,降低了面皮的弹性和回复性;通过微观结构分析可知,酶制剂可使蛋白质相互结合,蛋白质网络有明显的立体感.     

Sulfur in wheat gluten: In situ analysis by X-ray absorption near edge structure (XANES) spectroscopy

The sulfur containing gluten proteins largely determine the baking quality of wheat. In order to probe the speciation of sulfur, gluten proteins [gliadin, high molecular weight (HMW) and low molecular weight (LMW) subunits of glutenin], stored glutenin subunits as well as flour were investigated in situ by S K-edge X-ray near edge absorption structure (XANES) spectroscopy. The spectra confirmed the existence of disulfide bonds in oxidised (oxygen stream) glutenin subunits, supporting their significance for the formation of gluten networks. Additionally, glutenin subunits, which were stored under ambient air and temperature conditions, predominantly contained sulfur of higher oxidation states (sulfoxide, sulfonic acid). The disulfide state and also sulfoxide and sulfonic acid states were detected after reoxidation of glutenin subunits with potassium bromate.     

青稞和小麦醇溶蛋白和谷蛋白结构性质的比较研究

采用Osbron法分别提取青稞和小麦中的醇溶蛋白和谷蛋白,对这4 种蛋白质进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE）分析和红外光谱分析,并测定其表面疏水性、热稳定性、总巯基和二硫键含量。结果表明：醇溶蛋白在青稞蛋白质中的含量为16.96%,低于其在小麦蛋白质中的含量;谷蛋白在青稞蛋白质中的含量为47.83%,高于其在小麦蛋白质中的含量,但经SDSPAGE分析发现青稞中高分子质量谷蛋白亚基（high molecular weight glutenin subunit,HMW-GS）含量远低于小麦中的。青稞醇溶蛋白和谷蛋白中的二硫键和总巯基含量均低于小麦中的。4 种蛋白的表面疏水性差异不大。青稞谷蛋白的热稳定性高于小麦谷蛋白,不利于其吸收水分和部分展开。红外光谱分析发现小麦醇溶蛋白和青稞醇溶蛋白的二级结构主要由β-转角和β-折叠组成,而小麦醇溶蛋白中的β-转角所占比例更高;青稞谷蛋白和小麦谷蛋白的二级结构主要以β-折叠为主。     

Effect of different treatment methods on protein aggregation characteristics in wheat flour maturation

The effects of flour treatment methods, including with glucose oxidase (GOX), lipoxygenase (LOX), xylanase and heating for 1 h at 37 °C (HEAT), on protein aggregation during the flour maturation were investigated. GOX has strong oxidising effects; LOX not only oxidises, but also may affect unsaturated fatty acids; xylanase degrades sugar molecules; HEAT can accelerate the thermal motion of molecules. Data analysis after treatment with GOX, LOX, xylanase and HEAT revealed that the glutenin macropolymer content increased by 0.43%, 0.87%, 0.39% and 0.62%, and the median size of the sample (D₅₀) increased by 1.56, 1.64, 0.52 and 0.74 μm, respectively. In addition, the proportion of a random coil and β-sheet increased and that of α-helix and β-turns decreased, while the polymeric protein content increased. This study contributes to our understanding of the protein changes during flour maturation and helps to predict the quality of wheat flour.     

Wheat protein composition and properties of wheat glutenin in relation to breadmaking functionality

The unique breadmaking properties of wheat are generally ascribed to the visco-elastic properties of its gluten proteins. While monomeric gluten proteins (gliadin) show viscous behavior, polymeric gluten proteins (glutenin) are elastic. The unique elasticity of glutenin results to a large extent from its polymeric nature. Glutenin is a highly heterogeneous mixture of polymers consisting of a number of different high- and low-molecular-weight glutenin subunits linked by disulfide bonds. Although glutenin obviously is the major polymeric protein in wheat, other polymeric proteins occur as well. Their importance in breadmaking may be underestimated. Nevertheless, variations in both quantity and quality of glutenin strongly determine variations in breadmaking performance. Structural features of different classes of glutenin subunits are described. Variations in glutenin quality may result from variations in its (1) structure, (2) size distribution, and (3) subunit composition. Some hypotheses on glutenin structure and current insights into the role of glutenin size distribution are evaluated. Finally, different ways in which variation in glutenin composition may directly or indirectly (by affecting glutenin structure and/or size distribution) influence glutenin quality are discussed.     

亚麻籽胶及沙蒿胶对冻融面筋蛋白微观结构和持水性的影响

利用傅里叶变换红外光谱、扫描电子显微镜等方法研究亚麻籽胶（flaxseedgum,FG）及沙蒿胶（Artemisia sphaerocephala Krasch. gum,ASKG）对冻融循环处理后小麦面筋蛋白二级结构、微观结构、二硫键及持水性等的影响规律,以揭示亲水胶体对冷冻面团内面筋蛋白的保护机制。结果表明：冻融循环处理破坏了面筋蛋白网络结构的有序化,而FG及ASKG能够与面筋蛋白的网络结构交联形成稳定的交联结构。FG和ASKG添加量为0.4%时,面筋蛋白具有最为均匀致密的网络结构。FG和ASKG的添加整体上增加了面筋蛋白二硫键含量（52.21～90.49、52.21～83.44μmol/g）及α-螺旋相对含量（25.50%～34.57%、25.50%～34.36%）,使面筋蛋白结构在冻融循环条件下更加稳定。此外,FG和ASKG的添加还可使面筋蛋白表面疏水性降低（溴酚蓝结合量为152.3～110.89、152.3～97.14μg）,从而增强面筋蛋白对水分的束缚能力;胶体添加量为0.4%时持水力最大,分别是未添加胶体且经冻融处理的面筋蛋白组的1.46、1.43倍。综上,FG和ASKG...     

小麦粉吸水速率与其蛋白组成特性的关系

蛋白质理化特性的差异会导致小麦粉吸水速率的不同。本文以不同吸水速率的小麦粉为研究对象,测定面粉中粗蛋白含量、面筋蛋白含量、湿面筋含量、面筋指数、沉降值、谷蛋白溶胀指数、氨基酸含量及观测面团内部微观网络结构。结果表明,当粗蛋白含量13.25%降低到6.98%时,小麦粉的吸水速率从0.17 g/s增大到3.87 g/s;当麦醇溶蛋白含量从4.02%下降到1.53%及麦谷蛋白含量从5.28%下降到2.77%时,因形成的面筋膜的质量下降使小麦粉的吸水速率增大。同时吸水速率随湿面筋含量的减小而显著性增大,面筋指数对吸水速率无显著性影响。沉降值从69.50m L降到32.50 mL,谷蛋白溶胀指数从5.24%下降到3.33%,均与吸水速率呈显著性负相关(p0.05)。半胱氨酸含量从0.14%降低到0.04%,导致二硫键含量下降,使蛋白质间的分子作用力下降。当面团内部面筋网络结构紧密时,面粉成团时的阻力越大,其吸水速率越小。本研究表明蛋白质性质与小麦粉吸水速率呈负相关。     

麦谷蛋白聚合体含量与小麦粉质量性状相关性研究

利用9个小麦高世代品系(F7),含118个株系为研究材料,研究了蛋白质组分及谷蛋白聚合体(GMP)含量与微量SDS沉降值及面筋指数的相关性.结果表明:清球蛋白含量与微量SDS沉降值无相关性,谷蛋白含量与微量SDS沉降值及面筋指数均呈极显著正相关;GMP含量、GMP/TPP、GMP/CP、GMP/SGP以及TPP/CP对微量SDS沉降值有极显著的正向作用,其中GMP的贡献最大;GMP含量、GMP/TPP、GMP/CP与面筋指数呈显著或极显著正相关,其中GMP/TPP与面筋指数的相关性最高.偏相关分析表明:微量SDS沉降值变异平方和的60.58%可由其与TPP%、GMP%和GMP/SGP的线性关系来说明;通径分析结果显示:GMP含量与微量SDS沉降值的相关性主要是由其直接效应提供,GMP含量是影响微量SDS沉降值的第一因素.研究结果指出,西南麦区小麦品质改良中GMP含量,面筋指数可作为优质面条、馒头小麦的早代选择指标.     

魔芋葡甘聚糖对冷冻小麦面团面筋蛋白结构和功能特性的影响

为研究魔芋葡甘聚糖（konjac glucomannan,KGM）对冷冻小麦面团面筋蛋白分子质量、游离巯基、二级结构和微观结构及持水性、流变性、热特性的功能特性影响,从小麦粉中提取面筋蛋白,运用十二烷基硫酸钠-聚丙烯酰氨凝胶电泳、流变仪、差示扫描量热仪、紫外分光光度计、傅里叶变换红外光谱和扫描电子显微镜对冷冻小麦面团面筋蛋白结构和功能特性进行分析。结果表明,与对照相比,KGM显著增强了面筋蛋白的持水性,提高了面筋蛋白黏弹特性、变性温度（Tp）和变性焓（ΔH）。在KGM存在的情况下,面筋二级结构α-螺旋和β-折叠结构占比增加,β-转角结构和无规卷曲结构减少,使其在冷冻环境下更加稳定。扫描电子显微镜图像分析表明KGM取代度为1.5%时,面筋蛋白微观结构具有明显的海绵状结构和更大的孔隙。KGM对冷冻小麦面团中的面筋蛋白特性有显著影响,对面筋蛋白起到冷冻保护作用。     

谷朊粉、麦醇溶蛋白与麦谷蛋白基本性质研究

以溶解度、乳化性及乳化稳定性、起泡性及起泡稳定性为考察指标,系统研究不同pH 值条件下,谷朊粉、麦醇溶蛋白、麦谷蛋白的功能特性及其相互间关系。结果表明：pH 值3～11 范围内,谷朊粉的溶解度、乳化性及乳化稳定性、起泡性在pH7 时最小。在同一pH 值条件下,麦醇溶蛋白溶解度、乳化性及乳化稳定性、起泡性及起泡稳定性大于麦谷蛋白,且在乳化性及乳化稳定性方面,麦醇溶蛋白远大于麦谷蛋白。麦醇溶蛋白是提高谷朊粉功能特性的主要成分。