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。     

聚葡萄糖对面筋蛋白功能特性的影响

为了解聚葡萄糖对小麦面筋蛋白功能特性的影响,利用核磁共振仪、旋转流变仪、傅里叶红外和扫描电镜测定添加不同量聚葡萄糖对面筋蛋白的持水率、水分子存在状态、流变特性、蛋白二级结构和微观结构的影响。结果表明,随着聚葡萄糖浓度的增加,面筋蛋白的持水率呈增长趋势;在添加聚葡萄糖浓度6%时结合水含量最大为17.05%;弹性模量G′和黏性模量G″增大,添加6%浓度的聚葡萄糖使得tanδ值最小,聚合度最好;小麦面筋蛋白的二级结构β-折叠降低,添加6%聚葡萄糖时α-螺旋达到最大值15.66%;微观结构表明,添加6%浓度聚葡萄糖小麦面筋蛋白结构孔径变小,网络结构更均匀。由此显示聚葡萄糖可以改善面筋蛋白的功能特性。     

小麦面筋蛋白-果胶复合物的制备及功能特性研究

为了提高小麦面筋蛋白的溶解度,通过单因素和正交实验在湿热条件下制备了一种小麦面筋蛋白-果胶复合物,并研究了其功能特性的变化。结果表明:果胶添加量为1%,pH 4.5,温度50℃,反应时间60 min,小麦面筋蛋白-果胶复合物的溶解度达到10.44 mg/mL;与对照样品和混合物相比,该条件下所制备的小麦面筋蛋白-果胶复合物持水性、泡沫稳定性、乳化性和乳化稳定性均显著提高,持油性和起泡性显著降低。     

不同谷物麸皮对面团流变学特性及面筋蛋白结构的影响

本实验选用小麦麸皮、黑小麦麸皮、燕麦麸皮为原材料,探究在高添加量(质量分数30%)情况下不同谷物麸皮对面团流变学特性、面筋蛋白组成及结构的影响。结果表明,谷物麸皮含有丰富的膳食纤维,麸皮的加入使面团的吸水率、黏度崩解值显著增加,回生值显著降低,面团的形成时间、稳定时间虽与麸皮种类有关,但整体均呈上升趋势;添加麸皮的面筋蛋白中麦谷蛋白与麦醇溶蛋白比例增加了24.7%~73.0%、二硫键含量显著下降了26.0%~35.5%;面筋蛋白中的二级结构以β-折叠为主,小麦麸皮和黑小麦麸皮的加入使得面筋蛋白中的β-转角结构向β-折叠结构转化;扫描电子显微镜图显示麸皮的加入破坏了面筋蛋白原本均匀致密的微观结构。综上所述,谷物麸皮的加入改变了面筋蛋白的组成及二级结构,这些变化可能是导致面团流变学特性及面制品品质下降的原因。     

燕麦抗冻蛋白对面筋蛋白冻融稳定性的影响

将燕麦抗冻蛋白(AsAFPs)加入到小麦面筋蛋白中,通过测定冻融循环条件下的小麦面筋蛋白的持水性、持油性、乳化和乳化稳定性、二级结构和弛豫时间,研究AsAFPs对冻融小麦面筋蛋白品质的影响。结果表明:经过5次冻融循环后,小麦面筋蛋白的持水率由92.8%降到87.8%,而AsAFPs的加入能够减缓冻融循环过程中水分的流失,使小麦面筋蛋白的持水率由92.8%降到89.8%;小麦面筋蛋白持油性呈上升趋势,AsAFPs的加入可以减少疏水键的暴露,使小麦面筋蛋白持油性低于对照组;小麦面筋蛋白的乳化性降低,乳化稳定性升高,加入AsAFPs后,其乳化性升高,乳化稳定性降低;小麦面筋蛋白无规则卷曲、α-螺旋整体呈下降趋势,而β-折叠和β-转角整体呈上升趋势,加入AsAFPs后无规则卷曲、α-螺旋下降的幅度变小;小麦面筋蛋白的冻结水逐渐向自由水转变,AsAFPs组小麦面筋蛋白结合水和自由水的含量变化幅度均小于对照组。     

水分对冷冻小麦面团质构及面筋蛋白二级结构的影响

应用质构分析仪和傅里叶变换红外光谱仪测定小麦面团质构特性和微观结构(面筋蛋白二级结构),分析不同加水量对冷冻和未冷冻面团品质的影响。结果表明:加水量和冷冻对小麦面团的质构特性和面筋蛋白二级结构影响显著。随着加水量的增加,冷冻后小麦面团与未冷冻相比硬度增加、黏性升高、内聚性下降、弹性降低,而对面团的回复性影响很小。经冷冻后面团面筋蛋白的二级结构β-折叠和α-螺旋的相对含量增加,β-转角的相对含量降低,使面筋蛋白的网状结构趋于稳定。以上结果可以说明水分可能是影响冷冻面团品质的一个重要因素,也为进一步揭示加水量在小麦冷冻面团中的作用机理提供了重要的研究参考。     

牡丹花蕊蛋白对面团和面筋蛋白特性的影响

为实现牡丹花蕊资源化利用,以大豆分离蛋白为参照,研究牡丹花蕊蛋白对面团和面筋蛋白质构、动态流变学特性、二硫键、表面微观结构和二级结构的影响。结果表明,牡丹花蕊蛋白能够明显提高面团的硬度、黏着性和咀嚼性,添加量低于6%时效果优于大豆分离蛋白。添加花蕊蛋白提高了面团的储能模量与损耗模量,使得面团黏弹性增加。牡丹花蕊蛋白对面筋蛋白网络结构形成的影响与大豆分离蛋白基本一致,添加量为6%时,扫描电镜显示面筋蛋白气孔数量多且孔洞深,网络结构致密;面筋蛋白二级结构中,相对稳定的α-螺旋+β-折叠占比达到最大值59.32%,与空白组相比二硫键含量提高了89%。牡丹花蕊蛋白能够有效促进面筋蛋白网络结构的形成,提高面团的品质,可用于对黏弹性要求较高的面制品生产。     

小麦面筋蛋白琥珀酰化修饰研究

采用琥珀酸酐对小麦面筋蛋白进行改性修饰，系统研究了底物浓度、改性剂用量和反应温度对反应程度、溶解性、乳化性、起泡性和泡沫稳定性等蛋白功能特性的影响。优化出小麦面筋蛋白琥珀酰化的最佳条件：琥珀酰化底物浓度10％，琥珀酸酐用量15％，反应温度45℃。应用红外光谱对最优条件下改性的面筋蛋白结构进行了表征。将琥珀酰化改性后的小麦面筋蛋白添加至小麦粉中，面团粘着性提高32％。     

小麦面筋蛋白质的乙酰化改性

采用乙酸酐对小麦面筋蛋白质进行酰化改性 .结果表明 :小麦面筋蛋白质乙酰化的最佳反应条件为面筋蛋白质质量分数 5 % ,反应温度 35℃ ,乙酰酐用量为小麦面筋蛋白质用量的 15 % ;乙酰化改性后的面筋蛋白质 ,溶解度、乳化能力和起泡能力均得到了提高 ,乙酰化小麦面筋蛋白质对弱筋粉粉质特性的改善效果强于普通谷朊粉 .     

麦麸酚酸类物质对面团聚集态的影响

探究不同添加量的阿魏酸(FA)和咖啡酸(CA)对混合面团热机械学性质、面筋蛋白流变学性质和热力学性质的影响;同时研究FA和CA对面筋蛋白二级结构及微观结构的影响。结果表明,添加不同剂量的FA和CA对面团的吸水率、形成时间及黏度崩解值无显著影响,然而与对照组相比显著降低了稳定时间,提升了回生值。添加FA和CA显著提高了面筋蛋白的黏弹性模量,对面筋蛋白在10 Hz时损耗角正切值无显著影响。添加FA和CA降低了面筋蛋白的热降解温度、热变性温度和热变性焓值,显著增加了600℃时的热重损失率。面筋蛋白二级结构测定结果显示,添加FA和CA后β-折叠和α-螺旋的含量降低。与对照组相比,随着FA和CA添加量的增加,面筋蛋白的微观结构变得混乱无序。     

Effect of inulin on rheological properties of soft and strong wheat dough

The influence of inulin with different degrees of polymerisation (DP) on the farinograph characteristics, extensograph parameters and fermentation rheological properties of soft and strong wheat dough was explored. The results showed that the addition of inulin can reduce the water absorption of doughs, and inulin with lower DP had more significant effect and the influence on the soft dough was stronger than the strong dough. Inulin can enhance mechanical properties of the gluten network and improve the resistance to mixing of soft dough. The extensibility of doughs decreased with increasing inulin. Inulin increased the resistance to extension of soft dough; however, it is reverse for strong dough. Adding inulin significantly increased the volume of gas production and the maximum expansion height of doughs, and the effect of inulin with lower DP was more prominent. Additionally, the gas‐holding capacity of doughs was enhanced by inulin.     

The influence of inulin addition on the morphological and structural properties of durum wheat pasta

The effect of the addition of different concentration of inulin fibre to durum wheat pasta was evaluated in terms of structure, texture and morphological characteristics. Inulin fibre fraction was incorporated into pasta at 5%, 10% and 15% inclusion rates. Changes to pasta quality were observed with inulin fibre fraction addition by scanning electron microscopy, X-ray diffraction and Raman spectroscopy methods. Investigation of pasta microstructure indicate a lowering in crystallinity increasing the inulin content and characterisation of starch gelatinisation events indicated that a combination of changes to the starch–protein matrix and the high water-binding capacity of inulin alters the physico-chemical properties and then the digestibility of the pastas.     

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.     

Relationship between gluten degradation by Aelia spp and Eurygaster spp and protein structure

Gluten from wheat damaged by heteropterous insects loses its functionality after a short period of resting. In this study the properties of the gluten from damaged wheat are compared with that from sound wheat in order to understand the changes produced during incubation at 37 °C. The amounts of free thiol and amino groups were quantified, obtaining a marked increase of those groups during incubation of the damaged wheat. The thermal characterization of the damaged gluten showed a decrease in the denaturation temperature and a pronounced increase in the protein denaturation enthalpy after a short incubation, although the value of that enthalpy greatly dropped with a longer incubation period. The high‐molecular‐weight glutenin subunits (HMW‐GS) were rapidly hydrolysed while the low‐molecular‐weight glutenin subunits (LMW‐GS) showed a slower degradation. It seems that the HMW‐GS backbone was first hydrolysed, leading to a protein structure with higher thermal stability but, as the hydrolysis proceeded, a deeper degradation of the structure yielded a protein structure with lower denaturation enthalpy. The loss of gluten functionality results from complex changes in the gluten structure at the first and second level of the protein organization structure. Copyright © 2005 Society of Chemical Industry     

The interaction between inulin and wheat starch and effects of inulin on frozen storage quality of noodles

In this paper, the effects of adding a different proportion of inulin powder on starch gelatinisation, free amylose content, thermodynamic properties and microstructure of wheat starch were studied. RVA results showed that the addition of inulin could increase the starting temperature of wheat starch gelatinisation, decrease the peak viscosity and the setback value, and reduce the content of the leached amylose. In DSC test, similar trend was observed, starting temperature and peak temperature showed growing results, and retrogradation enthalpy and the ageing rate reduced. SEM results found that with inulin addition, wheat starch presents flocculent and fold structure. The noodles with 5% inulin addition were frozen-stored for 50 days after the cooking process. Inulin addition could retard the hardness and viscosity increase during the frozen storage. Besides, cooking loss rates and sensory property-treated samples were better than the control.     

膳食纤维与阿魏酸复配对面团和面筋蛋白性质的影响

研究膳食纤维(dietary fiber,DF)和阿魏酸(ferulic acid,FA)单一及复配添加对面团及面筋蛋白结构和性质的影响。结果表明,DF的添加使面团吸水率、形成时间、黏度崩解值分别显著增加了2.36%～7.76%、18.15%～69.18%、61.11%～283.33%,FA的添加使面团回生值显著增加了90.48%～97.62%,而FA与DF复配添加可改善二者对面团热机械学性质造成的影响;DF组和FA组面筋蛋白的黏弹性模量与对照组相比明显增加;DF组和FA组面筋蛋白的热变性温度(Tp)、热变性焓值(ΔH)、二硫键含量与对照组相比显著下降,质量损失率显著增大,表明添加DF、FA后面筋蛋白结构稳定性下降;扫描电子显微镜观察表明添加DF、FA后面筋蛋白平滑有序的微观结构变得松散、无序,而复合添加DF和FA后面筋蛋白的微观结构较单独添加等量DF、FA时有所改善。     

全麦粉的添加对油馕面团品质的影响

考察添加不同比例的全麦粉,对油馕面团粉质特性、拉伸性、糊化特性、混合粉溶剂保留特性、面团水分分布和面团面筋蛋白二级结构的影响。结果表明,随着全麦粉含量的增加面团加工性质变差,面团吸水率由65.18%增加至最大值80.30%,面团形成时间从4.13 min增加到最大值5.34 min;面团的峰值黏度、谷值黏度、回生值和衰减值呈下降趋势,而糊化温度则不断提高;拉伸能量由87 cm2降低至30 cm2,延展度由156 mm降低至92 mm,拉伸阻力由302 EU降低至242 EU。当全麦粉完全取代精粉时与精粉组相比（全麦粉取代率为0%）,混合粉的碳酸钠、蔗糖和水溶剂保留率分别增加了20.56%、18.69%和34.94%,而乳酸溶剂保留率则降低23.47%;核磁结果显示,面团中水分分布变化情况为A21/A2升高,A22/A2和A23/A2下降;傅里叶变换红外光谱仪测定结果显示,面筋蛋白结构中α-螺旋和β-折叠的总相对含量由68.57%下降为50.89%,无规卷曲相对含量增加了31.5%,稳定的二级结构下降、不稳定的二级结构相对含量上升,导致面筋蛋白结构变差。     

动态高压微射流对小麦面筋蛋白功能性质影响的研究

本文研究了动态高压微射流对小麦面筋蛋白功能性质的影响及其机理。结果表明:微射流对面筋蛋白功能性质的改变与其压力和蛋白浓度密切相关。随着压力的升高,在大于等于4%浓度时,溶解度先增大后减小,在80 MPa时达到最大值,在小于4%浓度时正好相反;蛋白浓度为4%时,起泡性减小,泡沫稳定性、乳化性和乳化稳定性增大,在100 MPa时达到最大,其他浓度例如2%和6%时正好相反。SDS-PAGE和DSC图谱显示,微射流使面筋蛋白大分子量亚基被破坏,形成新的具有更加紧凑的空间结构的水溶性聚集体,从而改变了面筋蛋白的功能特性。