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。     

谷朊粉改性研究进展

谷朊粉是一种营养丰富的植物蛋白资源,其特有功能性质在食品生产中具有广泛用途.通过一定生物化学手段改性,可大大拓宽谷朊粉应用范围.主要综述近年来有关谷朊粉物理、化学、酶法和基因工程改性方面的研究进展.     

小麦面筋蛋白糖基化改性研究进展

小麦面筋蛋白是麦谷蛋白和麦醇溶蛋白与水结合形成的独特产物,具有优良的黏弹性和延伸性,但是由于水溶性差,应用受到较大限制。蛋白质的糖基化修饰,是将糖类物质以共价键连接的方式导入蛋白质分子中,糖基化能改善面筋蛋白溶解性、乳化性和起泡性等性质,使其应用于不同领域。本文从面筋蛋白糖基化的机理、糖的种类、糖基化对面筋蛋白理化性质的影响、糖基化面筋蛋白的应用等方面综述了小麦面筋蛋白糖基化的研究进展。     

改性小麦谷朊蛋白提高其乳化性的研究进展

改性是提高小麦谷朊蛋白功能性质的重要手段。乳化性是蛋白质的重要功能之一。本文综述了以提高小麦谷朊蛋白乳化性为目的的物理、化学、酶法及复合改性等各种改性方法及近年来的进展,并对其应用进行了展望。      

小麦面筋蛋白结构及其改性研究

小麦面筋蛋白是生产小麦淀粉时副产品,具有价格低廉、产量大等特点。小麦面筋蛋白因分子量大、结构复杂、溶解性低而使其应用受限,因此在认识小麦面筋蛋白结构基础上,研究其结构及性能方面改性方法,对拓宽小麦面筋蛋白应用和缓解小麦过饱和问题都大有裨益。     

聚丙烯酸钠对小麦面筋蛋白流变学性能影响研究

采用AR1000型流变仪考察聚丙烯酸钠(PAANa)对小麦面筋蛋白改性的最佳工艺条件及改性前后流变学性能变化。结果表明,聚丙烯酸钠改性小麦面筋蛋白最佳工艺条件为,盐配比(Na2CO3∶K2CO3)=1∶9(w/w)、盐添加量1.0%、碱(NaOH)添加量1.0%、PAANa添加量0.04%、磁力搅拌时间60 min。动态实验中,改性前后小麦面筋蛋白临界应力分别为:当频率为10 Hz时,改性前后小麦面筋蛋白储能模量与损耗模量分别为4622 Pa、1723 Pa和76800 Pa、12384 Pa;稳态实验中,当蠕变5.5 min时,改性前后小麦面筋蛋白形变分别为11.06%和4.34%。恢复阶段中,当恢复到形变为3%时,改性前样品在实验时间内未能达到;而改性后小麦面筋蛋白恢复到此变形仅需6.2 min。由此可得出,聚丙烯酸钠优化小麦面筋蛋白品质。     

琥珀酸脱酰胺对小麦面筋蛋白酶解产物抗氧化性的影响

研究琥珀酸不同脱酰胺程度对小麦面筋蛋白胰酶的酶解产物抗氧化性的影响。在相同水解度下,以DPPH.清除率、.OH清除率、ORAC值为抗氧化指标,结果表明低脱酰胺程度(22.4%)的小麦面筋蛋白酶解产物的抗氧化性有较大幅度的提高,高脱酰胺程度(60.4%)的小麦面筋蛋白酶解产物的抗氧化性降低。水解度15%的酶解产物的肽分子量分布表明,低脱酰胺的小麦面筋蛋白酶解产物中分子量小于3000u的肽段增加,高脱酰胺的小麦面筋蛋白酶解产物中分子量小于3000u的肽段减少;在相同水解度下的氨基酸分析结果表明,脱酰胺后的小麦面筋蛋白酶解生成的肽的疏水性和抗氧化性的氨基酸含量提高。因此,低脱酰胺的小麦面筋蛋白酶解产物抗氧化性提高的主要原因是产物中含疏水性和抗氧化性氨基酸的小分子肽含量提高。      

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。     

Influence of double enzymic hydrolyses on gluten functionality

Functional properties of chemically deamidated and/or double enzymically‐treated gluten were studied. Performances of the modified glutens were compared to those of egg white proteins, casein, deamidated gluten and gluten submitted to deamidation plus single enzymic treatment. Higher nitrogen solubility index (>90%) was obtained after treatment of the gluten with the sequence pepsin + alcalase and deamidation + pepsin + papain. The sequence pepsin + papain has permitted the production of a gluten with foaming properties close to those of egg white. Deamidation + papain treatment leads to interesting emulsifying properties although different from those of casein. The results show that modified glutens present thresholds in the degree of enzymic hydrolysis (DH) for foaming and emulsifying properties (respectively 1.3% and 2.0%). For higher DH the stability decreases. © 1999 Society of Chemical Industry     

Improved functional properties of wheat gluten hydrolysate by covalent conjugation with chlorogenic acid

Appropriate modification of wheat gluten with polyphenols or other natural compounds can greatly increase its functional properties and provide a high-quality protein source at a relative lower price. In this paper, covalent modification of wheat gluten hydrolysate (WGH) was performed with chlorogenic acid (CGA) by free-radical grafting. The structural changes in WGH by conjugating with CGA were characterised by ultraviolet spectrum, FTIR spectroscopy, differential scanning calorimeter (DSC) and fluorescence scanning, as well as physicochemical properties and biological functions. Results showed that WGH-CGA conjugates had higher thermal stability, better emulsifying and foaming capabilities, stronger antioxidant activity and lower allergenicity than the non-conjugated WGH. These findings indicated that the WGH-CGA conjugates had potential use value as functional food materials and additives in the food industry.     

The effect of lactic acid bacteria fermentation on the antioxidant activity of wheat gluten pancreatin hydrolysates

The antioxidant activities of the fermented wheat gluten hydrolysates with different fermentation times were investigated to elucidate the impact of lactic acid bacteria (LAB) fermentation on the wheat gluten hydrolysates. Prior to LAB fermentation, wheat gluten was deamidated by hydrochloric acid and then hydrolysed by pancreatin to 12 and 24 h, respectively. Results showed that LAB fermentation had significant impacts on the enzymatic efficiency and antioxidant activities of wheat gluten. The degree of hydrolysis and protein recovery of hydrolysates gradually increased and then reached maximum values, respectively, when fermenting with LAB for 36 h. The hydrolysis degree and protein recovery of fermented pancreatin 24‐h hydrolysates were larger than that of the fermented pancreatin 12‐h hydrolysates during the whole fermentation. The antioxidant activity analysis revealed a marked increase and improvement in the scavenging activities of 1,1‐Diphenyl‐2‐picrylhydrazyl·radicals, hydroxyl radicals and oxygen radical absorbance capacity, while the scavenging activities of ABTS⁺ radical decreased as the fermentation time extended. The antioxidant activities of pancreatin 24‐h hydrolysates were higher than that of the pancreatin 12‐h hydrolysates during the whole LAB fermentation.     

小麦蛋白对TGase酶交联改性大豆蛋白凝胶特性的影响及机制

为探讨TGase酶对大豆与小麦混合蛋白凝胶性质的影响,本文研究了小麦蛋白的加入前后混合蛋白凝胶功能性质的变化规律。通过研究TGase酶添加量、反应温度、反应pH对混合蛋白凝胶特性的影响可知:蛋白浓度为11%（11 g/100 mL）保持不变,TGase酶添加量为30 U/g,反应温度为40℃,反应pH为7.0时,TGase酶对混合蛋白凝胶特性改善效果最强。对比小麦蛋白加入前后蛋白凝胶的性质,发现小麦蛋白的添加使得蛋白结构的β-折叠含量升高,游离巯基含量减少,凝胶弹性模量（G’）增强,形成了更为多空且紧密有序的三维网络结构,使得混合蛋白的凝胶性能显著增强（p<0.05）。      

乳糖改性提高谷朊粉乳化性研究

研究了谷朊粉与乳糖在控制条件下通过Maillard反应对谷朊粉乳化性的改善作用。结果表明,乳糖改性明显地改善了谷朊粉的乳化活性(Emulsion Activity Index,EAI), 通过正交实验,得到Maillard反应改善谷朊粉乳化性的最佳条件为:pH7、谷朊粉/乳糖比为3:1、谷朊粉浓度为12%、反应时间为10d,此条件下的EAI为33 02m2/g;由方差分析可得,各因素对提高谷朊粉乳化性的重要性按大小次序为pH>谷朊粉/乳糖比>谷朊粉浓度、反应时间,通过方差分析显示诸因素对乳化性的影响没有显著差异。     

小麦面筋蛋白改性技术的研究

小麦面筋蛋白来源广泛,价格低廉,是良好的植物蛋白资源。综述了小麦面筋蛋白的改性技术,分别介绍了物理方法、化学方法、生物酶法以及基因工程法,不同的改性方法对小麦面筋蛋白的功能特性均有了较大程度的改变。对不同的改性方法的优缺点也做了简要描述。从国内外的研究情况来看小麦面筋蛋白的应用前景是十分广阔的。     

Effect of citric acid deamidation on in vitro digestibility and antioxidant properties of wheat gluten

The effects of citric acid deamidation on the physiochemical properties of wheat gluten were investigated. In vitro digestion was carried out to determine changes of molecular weight distribution, amino acids composition and antioxidant efficacy of wheat gluten hydrolysates. Results indicated that citric acid deamidation significantly increased gluten solubility and surface hydrophobicity, at a neutral pH. Deamidation induced molecular weight distribution change of gluten with little proteolysis. Results from FTIR indicated that the α-helix and β-turn of deamidated gluten increased accompanied by a decrease of the β-sheet structure. After deamidation, in vitro pepsin digestibility of wheat gluten decreased, while in vitro pancreatin digestibility increased. The oxygen radical absorbance capacity (ORAC) activity of the in vitro digests decreased with increase of deamidation time. The high Lys and total essential AAs amounts in the final digests suggested that the nutritional values of wheat gluten after deamidation might be enhanced.     

小麦面筋蛋白酶解特性研究

采用风味蛋白酶对小麦面筋蛋白进行深度水解,通过单因素实验,分析了底物浓度、温度、pH、酶用量、反应时间对水解度和蛋白质提取率的影响,并通过正交实验确定制备酶改性小麦面筋蛋白的最佳工艺参数为:底物浓度5%,T=50℃,pH6.5,酶用量=80LAPU/g,水解时间7h。反应最终可得水解度和蛋白质提取率均很高,且没有苦味的植物蛋白水解液,其中酶解液的水解度可达28.03%,蛋白质提取率可达52%。     

小麦面筋蛋白盐酸脱酰胺工艺优化及其酶解敏感性

文以小麦面筋蛋白为原料,优化了盐酸对小麦面筋蛋白的脱酰胺工艺,比较了最佳脱酰胺工艺下的小麦面筋蛋白在胰酶、风味蛋白酶和碱性蛋白酶酶解过程中蛋白回收率和水解度的变化,并对其酶解36 h酶解液的自由基吸收能力(ORAC)抗氧化特性进行分析评价。研究结果表明,盐酸脱酰胺的工艺条件是:小麦面筋蛋白浓度为24%,0.30 mol/L的HCl,65℃,24 h脱酰胺;在该工艺条件下,胰酶酶解液蛋白回收率和水解度最高,酶解效果最好;高脱酰胺程度小麦面筋蛋白在胰酶酶解36h后酶解液的蛋白回收率和水解度高于低脱酰胺程度的酶解液;ORAC抗氧化特性分析表明高脱酰胺程度小麦面筋蛋白酶解液的ORAC值高于低脱酰胺程度的酶解液,其ORAC值最高为(689.67±10.22)μmol Trolox/g。     

小麦面筋蛋白的性质和转谷氨酰胺酶对其成膜性能的影响

以小麦面筋蛋白为研究对象,探讨小麦面筋蛋白的性质,转谷氨酰胺酶的作用和制备条件对膜性能的影响。结果表明,酶用量为20U/g,反应时间为120min,pH为11,甘油/谷朊粉1:2.5,塑料平板作为成膜介质和乙醇体积分数均为40%～50%时,膜的抗拉强度增加51%,阻水性提高23%,透光率提高了5.48倍。扫描电镜显示膜的超微结构更加细致光滑。说明蛋白质的性质对其成膜性能的影响至关重要,酶处理有助于改善膜的机械性能和透光性,选择合理的制备条件,可得到性能优良的小麦面筋蛋白膜。