有限酶解对谷朊粉功能性质的影响

为了改善谷朊粉在水溶液中的分散特性,又保留其蛋白质大分子的功能性质,利用碱性蛋白酶对谷朊粉进行了有限水解,研究了谷朊粉的有限酶解条件对酶解物全成分的分散特性、乳化性、发泡性等功能性质以及水解度的影响。结果表明,酶解后谷朊粉在水中的分散性大大提高,而乳化能力和起泡特性则依底物浓度、酶解温度、加酶量和反应时间等因素发生不同的变化。综合评价结果可知,在谷朊粉浓度0.30 g/mL、酶解温度50℃、酶对底物的质量分数为0.75%、反应时间20 min条件下所得酶解物具有较好的功能特性,分散性为0.962,乳化能力为84.3 mL油/g蛋白,起泡性为52 mL。     

盐酸处理对谷朊粉理化性质改良的研究

利用盐酸处理改善谷朊粉的溶解度、乳化性、起泡性等理化性质,研究盐酸与谷朊粉的相对浓度、反应温度、反应时间、盐酸浓度对谷朊粉理化性质的影响。结果表明,盐酸处理改良谷朊粉理化性质的最佳条件:谷朊粉质量百分比为8%,盐酸∶谷朊粉为3.5∶100(质量比),反应温度65℃。试验证明,盐酸处理对谷朊粉的溶解度、乳化性及其稳定性、起泡性及其稳定性都有显著作用。     

糖基化改性对谷朊粉功能性质的影响

采用葡萄糖、乳糖和葡聚糖对谷朊粉进行糖基化改性,研究糖基化改性对谷朊粉功能性质的影响.结果表明:谷朊粉与葡萄糖和乳糖的反应速度比葡聚糖高,体系的褐变程度和接枝度也比葡聚糖大;三种糖与谷朊粉反应后均能改善谷朊粉的溶解性,且最大溶解度相当,约为反应前的3倍;糖基化反应也能增强谷朊粉的乳化性,其中谷朊粉与葡聚糖反应产物的乳化活性和乳化稳定性明显高于谷朊粉与葡萄糖和乳糖的反应产物;此外,糖基化使谷朊粉的表面疏水性增加,并且谷朊粉与葡萄糖和乳糖的反应产物的表面疏水性增加程度高于谷朊粉与葡聚糖的反应产物.     

湿热处理提高谷朊粉乳化性的研究

以谷朊粉为原料，研究了利用湿热处理对谷朊粉乳化性的改善作用，通过pH值、谷朊粉质量分数、加热温度及时间对谷朊粉乳化性的影响，确立了4因素3水平的正交实验，探讨了湿热处理提高谷朊粉乳化性的最佳条件。结果表明：各因素对提高谷朊粉乳化性的明显程度依次为：pH值＞谷朊粉质量分数＞温度＞时间。正交试验分析表明，湿热处理提高乳化性的最佳作用条件为：pH值为4．0、谷朊粉质量分数为9．0％、时间为20min和温度为100℃。在最佳条件下，谷朊粉的乳化活性及乳化稳定性均为100％，溶解度为48．4％。说明湿热处理显著提高了谷朊粉的乳化性。     

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。     

谷朊粉可食性膜研究进展

该文介绍了可食性膜分类,并从谷朊粉性质、谷朊粉复合膜研究现状、谷朊粉与其他成膜材料如多糖、蛋白质、脂类复合改性及对谷朊粉和谷朊粉复合膜的化学改性进行了综述,并对谷朊粉膜研究方向进行展望。     

谷朊粉可食性膜研究进展

该文介绍了可食性膜分类,并从谷朊粉性质、谷朊粉复合膜研究现状、谷朊粉与其他成膜材料如多糖、蛋白质、脂类复合改性及对谷朊粉和谷朊粉复合膜的化学改性进行了综述,并对谷朊粉膜研究方向进行展望。     

微波处理提高谷朊粉乳化性的研究

以谷朊粉为原料，研究了利用微波处理对谷朊粉乳化性的改善作用，通过pH值，谷朊酚浓度，微波能量及加热时间对谷朊粉乳化性的影响，确立了四因素三水平的正交实验，探讨了微波处理提高谷朊酚乳化性的最佳条件。结果表明：各因素对提高谷朊粉乳化性的明显程度依次为：加热时间＞pH值＞谷朊粉浓度＞微技能量。正交试验分析表明，微波处理提高乳化性的最佳作用条件为：pH值＝10．0、谷朊粉浓度＝9．0％、加热时间=100和微波能量＝560W。在最佳条件下，谷朊粉的乳化活性及乳稳定性均为100％，溶解度＝37．6％。说明微波处理显著提高了谷朊粉的乳化性。     

去酰胺作用对谷朊粉功能特性影响研究

该研究采用盐酸改性谷朊粉,探讨盐酸浓度、反应温度、反应时间对去酰胺样品乳化性、溶解性影响。结果表明,去酰胺作用使谷朊粉功能性质显著改善,可使原谷朊粉乳化性、溶解性都有极大提高。     

复合添加剂在速冻馒头中的应用研究

本文研究了谷朊粉、Vc、CMC—Na、硬脂酸乳酸钠以及它们的复合对速冻馒头品质的影响，结果表明，适量的谷朊粉、Vc、CMC—Na、硬脂酸乳酸钠对速冻馒头的品质均有改善作用：复配改良剂的最优组合为：谷朊粉2％，Vc0．006％，CMC—Na0．6％，硬脂酸乳酸钠0．3％。     

小麦面筋蛋白乙酰化及琥珀酰化改性对功能性改善效果的比较及反应机理初探

本研究采用乙酸酐及琥珀酸酐对小麦面筋蛋白进行酰化改性，比较乙酰化及琥珀酰化改性对小麦面筋蛋白功能性的改善效果，对酰化反应的机理进行了初步研究。结果表明，在相同的反应条件下，琥珀酰化反应对小麦面筋蛋白功能性的改善效果强于乙酰化反应；小麦面筋蛋白的酰化是在面筋蛋白中引入酰基，改变蛋白结构，从而提高其功能性的过程。     

Effect of acetic acid deamidation‐induced modification on functional and nutritional properties and conformation of wheat gluten

BACKGROUND: Acids are often used for deamidating proteins, but the literature on acetic acid deamidation of proteins is sparse. Previous research on acetic acid‐induced modification of proteins has focused on peptide proteolysis by relatively high concentrations of acetic acid (>1.5 mol L^?1) rather than on the accompanying effect of deamidation. Therefore the objective of this study was to determine the deamidation effect of acetic acid with as little peptide proteolysis as possible by employing low‐concentration acetic acid (<0.05 mol L^?1) to deamidate wheat gluten. Changes in surface hydrophobicity, conformation, functional properties and nutritional characteristics of acetic acid‐modified samples were determined and compared with those of hydrochloric acid (HCl)‐modified samples. RESULTS: At similar degree of deamidation and nitrogen solubility index, samples deamidated with acetic acid showed less destruction of peptides bandings, better foaming properties and a more decompacted form (lower S? S content in protein as determined by Raman spectroscopy) than those deamidated with HCl and also exhibited improved emulsification capacity and emulsion stability compared with native wheat gluten. Acetic acid deamidation led to fewer changes in peptide molecular size and secondary structure of wheat gluten compared with HCl deamidation according to the results of sodium dodecyl sulfate polyacrylamide gel electrophoresis and Fourier transform infrared spectroscopy respectively. Amino acid analysis revealed that the nutritional characteristics of wheat gluten were well maintained after deamidation with acetic acid. CONCLUSION: The results show that low‐concentration acetic acid can modify wheat gluten mainly by deamidation, resulting in deamidated wheat gluten with good functional and nutritional properties. Copyright © 2009 Society of Chemical Industry     

Acylation of Starch using Trifluoroacetic Anhydride Promoter

The use of trifluoroacetic anhydride as a promoter for the acylation of granular starch is reported. Efficient acylation in a homogeneous solution is attained when the carboxylic acid of interest and trifluoroacetic anhydride are added, the latter in at least twice molar excess to the hydroxyl groups of the anhydroglucose residues. The reaction necessitates prior heating of granular starch in acetic acid before the acylation reagent is added. The product is an acylated starch with degrees of substitution (DS) of 2 to 3, as analyzed by gas‐liquid chromatography or high‐pressure liquid chromatography. Lower molar ratios of trifluoroacetic anhydride to the anhydroglucose residue gave lower degree of substitution. Additionally, starch acetates with different degree of substitution are prepared by addition of limited amounts of the acylation reagent or by partial de‐acetylation of starch triacetate with sodium methoxide. Starch esters are prepared from acetic, butanoic, hexanoic, octanoic, palmitic and benzoic acids.     

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。     

优质玉米蛋白开发研究

该文通过玉米蛋白酶解,再对其水解物进行琥珀酰化改性,以便开发功能性质优良的玉米蛋白质,并分析复合改性对蛋白质功能性质和其结构参数的影响。研究发现:蛋白酶对玉米蛋白质有良好水解效果,水解度可达29.47％,随着酰化试剂用量增大,蛋白质酰化程度得以逐步提高。玉米蛋白质水解物(DH3.0)比原蛋白质更易被琥珀酰化,琥珀酰化对蛋白质水解物水溶性、乳化性、疏水性和结柔性影响比原蛋白质更显著,因而复合改性(酶解—酰化)是改变蛋白质功能性质更优良方法。     

小麦面筋蛋白改性研究进展

对小麦面筋蛋白的性质及改性的研究现状进行了综述,其中包括物理改性、化学改性、酶改性和基因工程改性。小麦面筋蛋白经改性后,其溶解性、乳化性和起泡性等功能特性得到提高,从而拓宽了应用范围。本文还对小麦面筋蛋白改性今后的研究提出了新的思路。     

EFFECT OF BAKING INGREDIENTS AND MIXING DURATION ON DOUGH DEVELOPMENT, GAS RELEASE AND BREAD MAKING PROPERTIES

Three trials were carried out to determine the effect of wet gluten, acetic acid, fat, sodium chloride and mixing duration on dough development, gas release and bread characteristics using regression analysis. Maximum dough height was significantly affected by acetic acid, wet gluten, mixing duration and sodium chloride whereas maximum gas formation was significantly affected by acetic acid and sodium chloride levels. The addition of fat had significant effects on bread volume. Sodium chloride affected overall acceptability followed by wet gluten, mixing duration and fat levels. Bread volume and overall acceptability decreased with an increase in mixing duration. Increased levels of sodium chloride increased bread volume and overall acceptability and decreased CO₂ production. Addition of fat at a level of more than 3% caused a decrease in acceptability. Bread volume and acceptability progressively increased with the increase in wet gluten levels.     

谷朊粉的功能特性及改性研究

通过一定方法改性之后的谷朊粉,在食品等工业化生产中有着广泛的应用。本文论述了谷朊粉的化学组成和功能特性,以及近年来对谷朊粉改性的研究进展。     

琥珀酰化度大小对改性小麦面筋蛋白性质影响的研究

本文采用琥珀酸酐对小麦面筋蛋白进行酰化改性，讨论了琥珀酰化度大小对面筋蛋白的溶解性、乳化性、乳化稳定性、起泡性和起泡稳定性影响，并对最佳改性条件下改性小麦面筋蛋白进行了在面条加工中的应用研究。结果表明：琥珀酰化度为66．1％时改性效果最好，改性面筋蛋白的溶解度、乳化及乳化稳定性、起泡及起泡稳定性分别为5．09mg／ml，56．8％，56．4％，44．8％，25％；利用最佳改性条件下的琥珀酰化面筋蛋白生产面条，面条的综合性能均比未改性的面筋蛋白品质高。     

Untersuchungen über Einsatzmöglichkeiten von Weizenkleber in chemisch-technischen Bereichen

Studies on the Application of Wheat Gluten in Chemo-technical Fields . Vital wheat gluten can be converted into a soluble modification by sufficiently lasting reaction with acrylonitrile. The reaction in alkali is accompanied by side chain deamidation and allows yields up to 85 or 90%. The modified gluten can be used as co-binder in paper coating formulations. Sodium hydroxide and ammonia solutions have been tested as solvents. Viscosity and water retention of model coating formulations can be varied within a wide range. Using reaction times between 18 and 240 h binding strength of manually coated papers which have been prepared with paper coating formulations having cyanoethylated wheat gluten as a co-binder and which were tested in IGT tests proved to be equivalent to experiments in which modified soybean protein has been used as standard co-binder. Comparable results have been achieved with papers made in semi-technical coating experiments. Also, further properties of coated paper (e. g. gloss, whiteness, and wet-strength test) showed to be successful with modified gluten. Informal modification by means of succinic anhydride achieved sucess, too. Regarding the strength of wood material glueing encouraging results were obtained with vital wheat gluten or with gluten fractions as filler in urea formaldehyde resins glues. Acetic acid treated gluten which has been plastified by intense mechanical process could be used in filling collagen. This mixture could be supplied as raw material for artificial edible sausage casings without any loss in quality.