美拉德反应对豌豆蛋白水解物乳化性和抗氧化性的影响

本文考察了美拉德反应对不同商业蛋白酶(碱性蛋白酶、风味蛋白酶和复合蛋白酶)制备的豌豆蛋白水解物的理化性质、乳化性和抗氧化性的影响。豌豆蛋白水解物分别与葡萄糖、麦芽糊精和葡聚糖在pH7.0,60℃保温48h。结果:体系反应48h后游离氨基含量下降;希夫碱含量增加;反应物荧光强度下降。表明,豌豆蛋白水解物与糖发生了共价结合。SDS-PAGE进一步证实了高分子共聚物的生成。美拉德反应显著提高了风味蛋白酶和复合蛋白酶水解物的乳化能力,尤其是复合蛋白酶水解物与葡聚糖的反应产物表现出了极好的乳化活性和乳化稳定性。各美拉德反应产物均具有显著抑制脂质体氧化的能力(p<0.05)。所有糖中,葡聚糖制备的反应物具有最高的乳化活性和抗氧化活性。因此,葡聚糖参与的美拉德反应可作为提高豌豆蛋白水解物乳化性的一种有效方法,并完好保留水解物的抗氧化活性。     

响应面试验优化超声系统中玉米醇溶蛋白-葡聚糖糖基化及其性质分析

采用超声波技术辅助玉米醇溶蛋白与葡聚糖进行美拉德反应,通过单因素及响应面试验研究玉米醇溶蛋白-葡聚糖美拉德反应的工艺,并对糖基化产物的结构及功能性质进行测定。结果表明：当超声时间50.15?min、超声功率300?W、糖质量浓度0.025?g/mL时,玉米醇溶蛋白-葡聚糖复合物的接枝度达到最大,与同条件的水浴加热反应产物相比,接枝度由10.13%提高到18.28%,接枝度提高了44.58%。对反应后玉米醇溶蛋白进行傅里叶红外光谱分析发现,玉米醇溶蛋白与葡聚糖通过共价键结合,证明美拉德反应发生。对反应产物的功能性测定发现,与天然蛋白和水浴加热反应糖基化产物相比,超声系统中的糖基化产物的溶解性、乳化性和乳化稳定性、起泡能力和泡沫稳定性均显著提高,说明超声技术能够提高糖基化反应效率,改善产物的结构及性质,拓宽了玉米醇溶蛋白的加工利用的领域。     

糖的种类对海参蛋白美拉德反应产物性质影响研究

以海参蛋白为研究对象，分别选择葡萄糖、果糖、乳糖、麦芽糖、葡聚糖为糖源，探究糖的种类对海参蛋白美拉德产物性质的影响，并对海参蛋白与糖在不同反应时间和pH条件下所得产物性质进行分析。通过接枝度、溶解性和乳化性的测定，得出接枝度大小依次为葡萄糖、乳糖、麦芽糖、果糖和葡聚糖糖化产物，溶解性整体基本随pH和反应时间的增大呈上升趋势，乳化性随反应时间的延长明显提高。基于傅里叶变换红外光谱和差示热量扫描法对不同种类糖和海参蛋白的美拉德反应产物的进行结构表征，结果表明，海参蛋白在糖化反应后3348 cm-1附近的峰向低波数发生了移动，移动的大小为葡萄糖<果糖<乳糖<麦芽糖<葡聚糖，说明糖化过程中发生了氢键缔合，同时海参蛋白美拉德产物的变性峰温度有所提高，稳定性增强。本研究为海参的高值化利用提供基础数据支撑。     

ε-聚赖氨酸与葡聚糖美拉德反应初级阶段产物的乳化性研究

采用美拉德干热反应制备ε-聚赖氨酸-葡聚糖共价复合物并制备乳液,通过浊度、粒径及稳定性分析,研究了反应温度、湿度、时间、反应物混合比和pH对共价复合物乳化性及乳化稳定性的影响。褐变程度及接枝度结果表明,ε-聚赖氨酸和葡聚糖发生了美拉德反应。以乳化性改善为主要指标,ε-聚赖氨酸/葡聚糖质量比1∶15,在pH8.5,相对湿度为65%,60℃条件下,干热反应1～3d产物的乳化性及乳化稳定明显改善,反应1d复合物乳化性较好且褐变程度较小,接枝度约26.4%。以乳化稳定性改善为指标,ε-聚赖氨酸/葡聚糖质量比1∶10,反应1d最佳。     

美拉德反应对燕麦β-葡聚糖乳化性能影响的研究

通过美拉德反应对燕麦β-葡聚糖进行改性以期提高其乳化性。燕麦β-葡聚糖与L-谷氨酰胺(质量比10∶1、5∶1以及2∶1)发生美拉德反应,监测反应进程,对产物的结构进行表征,进而考察了其乳化性能及表面张力。结果表明,随美拉德反应的进行,体系的p H减小(p0.05),紫外吸光值和荧光吸光值增大(p0.05),燕麦β-葡聚糖美拉德反应后,产物有β-葡聚糖特征吸收峰和氨基酸的特征吸收峰;β-葡聚糖的分子量增大,且随L-谷氨酰胺添加比例的增加而增大。随着反应时间和L-谷氨酰胺添加比例的增大,产物乳化活性和乳化稳定性增大(p0.05),表面张力减小(p0.05)。     

抗冻融大豆蛋白的制备

采用湿法美拉德反应对大豆蛋白进行糖基化改性,研究了糖基化接枝产物的冻融稳定性。结果表明,湿法糖基化大豆蛋白能有效提高接枝产物的冻融稳定性,在SPI(大豆分离蛋白)浓度40 mg/m L、蛋白与糖质量比1∶3、反应时间4 h、p H 8.0、反应温度95℃条件下的接枝物冻融前后的EAI(乳化活性)分别是未改性蛋白的1.69倍和1.76倍,ESI(乳化稳定性)是未改性蛋白的1.37倍和1.27倍。傅里叶红外光谱分析表明,SPI-D接枝物在1 000 cm-1附近有较强的吸收,在3 700~3 200 cm-1处有一个更宽的振动伸缩吸收,葡聚糖以共价键的形式接入到SPI上。SPI-D接枝物在激发波长为347 nm,发射波长在435 nm处有最大的荧光强度,符合美拉德反应产物的荧光特性,进一步证明SPI与葡聚糖发生了美拉德反应。     

3种还原糖对芸豆清蛋白糖基化改性产物乳化性及结构的影响

将葡萄糖、乳糖、果糖与紫花芸豆清蛋白(kidney bean protein,KPI)进行美拉德反应,并分析美拉德反应产物的乳化性及结构变化。结果表明,可通过与葡萄糖、果糖和乳糖发生美拉德反应来改善芸豆蛋白的乳化活性及乳化稳定性,其中果糖改善效果最好,芸豆蛋白的乳化性由原来的37.52m2/g增加为98.69m2/g,乳化稳定性由16.88min增加到28.68min;芸豆蛋白与还原糖发生美拉德反应后,蛋白空间结构发生变化,表现为表面疏水性增强,表面巯基和总游离巯基含量降低,紫外吸收增加,内部荧光强度降低且发生红移,更利于蛋白吸附到油水界面,增强其乳化性。     

美拉德反应对玉米蛋白水解物功能特性的影响

研究美拉德反应对玉米蛋白水解物功能特性的影响。玉米蛋白水解物(zein protein hydrolysate,ZPH)和半乳糖(galactose,Gal)按照1∶2质量比在不同p H值条件下进行美拉德反应,通过测定溶解性、起泡性质、表面疏水性、抗氧化能力以及乳化性质的变化趋势,进一步分析美拉德反应对ZPH功能特性的影响。研究结果表明,不同的pH值条件下,美拉德反应产物功能特性受到加热时间的影响。随着pH值的升高,美拉德反应产物的起泡性质、溶解性、抗氧化能力以及乳化性表现出先下降后上升的变化形势,表面疏水性显著降低(P 0.05)。除此之外,与其他两个处理组相比,加热6 h的美拉德反应产物的起泡性、溶解性、抗氧化能力以及乳化性都最高,而表面疏水性最低(P0.05)。     

美拉德反应制备等电点澄清透明的乳清分离蛋白研究

本文旨在以乳清分离蛋白(WPI)为原料,研究其与糖类物质的美拉德反应制备得到产物在等电点附近的溶解性、乳化性(EAI)、乳化稳定性(ESI)和热稳定性等功能特性,为其在透明饮料中的应用奠定基础。在相对湿度79%,温度70℃的反应条件下制备得到乳清分离蛋白与L-乳糖的美拉德反应产物,聚丙烯酰胺凝胶电泳(SDS-PAGE)实验结果证实了美拉德反应使WPI中α-乳清蛋白和β-乳球蛋白分子量分别增加2~3 ku左右;邻苯二甲醛(OPA)结果表明在美拉德反应时间为12 h时,WPI中游离氨基酸含量减少35%左右;美拉德反应改性使其溶解性、乳化性(EAI)、乳化稳定性(ESI)和热稳定性都有显著提高(在10 min时EAI和ESI分别为0.35 m~2/g和20 min,为WPI的1.5倍和1.7倍);电位和粒径结果显示,乳清分离蛋白糖基化产物的溶解性和热稳定性增强是因为蛋白质表面引入糖分子的位阻效应所致,而非静电作用。     

抗坏血酸对蛋白基美拉德反应产物的性质影响

为了研究抗坏血酸对乳清蛋白美拉德反应产物的影响,对反应产物的各项理化性质进行了对比。结果表明,抗坏血酸对乳清蛋白美拉德反应有明显影响:在有抗坏血酸参与的情况下,反应产物的乳化性、起泡性、溶解性等加工特性没有降低,热稳定性有明显提高、游离氨基酸得到提高。总之,抗坏血酸对蛋白质美拉德反应产物的加工特性有所改善。     

The dual effects of Maillard reaction and enzymatic hydrolysis on the antioxidant activity of milk proteins

The objective of this study was to determine the enhanced effects on the biological characteristics and antioxidant activity of milk proteins by the combination of the Maillard reaction and enzymatic hydrolysis. Maillard reaction products were obtained from milk protein preparations, such as whey protein concentrates and sodium caseinate with lactose, by heating at 55°C for 7 d in sodium phosphate buffer (pH 7.4). The Maillard reaction products, along with untreated milk proteins as controls, were hydrolyzed for 0 to 3 h with commercial proteases Alcalase, Neutrase, Protamex, and Flavorzyme (Novozymes, Bagsværd, Denmark). The antioxidant activity of hydrolyzed Maillard reaction products was determined by reaction with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, their 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, and the ability to reduce ferric ions. Further characteristics were evaluated by the o-phthaldialdehyde method and sodium dodecyl sulfate-PAGE. The degree of hydrolysis gradually increased in a time-dependent manner, with the Alcalase-treated Maillard reaction products being the most highly hydrolyzed. Radical scavenging activities and reducing ability of hydrolyzed Maillard reaction products increased with increasing hydrolysis time. The combined products of enzymatic hydrolysis and Maillard reaction showed significantly greater antioxidant activity than did hydrolysates or Maillard reaction products alone. The hydrolyzed Maillard reaction products generated by Alcalase showed significantly higher antioxidant activity when compared with the other protease products and the antioxidant activity was higher for the whey protein concentrate groups than for the sodium caseinate groups. These findings indicate that Maillard reaction products, coupled with enzymatic hydrolysis, could act as potential antioxidants in the pharmaceutical, food, and dairy industries.     

Functional properties of the Maillard reaction products of rice protein with sugar

The glycation of rice proteins with reducing sugars was investigated in an attempt to improve their solubility and functionality. Rice proteins isolated from a Chinese milled medium-grain rice were glycated with glucose, lactose, maltodextrin, or dextran in 2% aqueous dispersions. The sugar that provided the most improvement of the solubility, emulsification activity (EA) and emulsification stability (ES) of the Maillard reaction products was glucose. The optimum reaction conditions were at pH 11, 100 °C, and reaction time 15 min, which increased the solubility, EA and ES of rice protein from 20%, 0.46 and 11.1 to 92%, 0.64 and 18.2, respectively. Extending the reaction time beyond 15 min continued the development of latter-stage Maillard browning products without improvements in the functional properties of the Maillard reaction products. SEC–HPLC analysis with light scattering detection showed a decrease of the weight-averaged molecular weight from 500 to 100 K during the initial 15 min.     

Functional properties of Maillard reaction products of rice protein hydrolysates with mono-, oligo- and polysaccharides

The Maillard reaction was carried out under wet reaction conditions using rice protein product from limited hydrolysis to conjugate with various mono-, oligo- and polysaccharides. The Maillard reaction products (MRPs) prepared with rice protein hydrolysates at 5% degree (hydrolysed by Protease N) and dextran T20 (20 min at 100 °C) showed the greatest improvement in functionality. The solubility, emulsification activity (EA), and emulsification stability (ES) of the MRPs increased by factors of 3.5, 5.3 and 7.3 times, respectively as compared to MRPs formed with native rice proteins and dextran T20. Amino acid analysis indicated that lysine and arginine decreased significantly in the MRPs. Formation of MRPs reduced the surface hydrophobicity, which was in agreement with the change of solubility. However, further decreasing of the surface hydrophobicity resulted in lower EA and ES during the late stage of the reaction. Fluorescence analysis suggested that formation of late stage MRPs occurred after 20 min of the Maillard reaction. The molecular weight distributions showed that the functional properties of MRPs and the mechanisms of formation were affected by the peptide chain length.     

美拉德反应及其产物对绍兴酒的影响

美拉德反应在食品的加工、贮存过程中是一类常见的化学反应。由于绍兴酒中能参与美拉德反应的糖类和氨基类化合物含量丰富，因此美拉德反应是绍兴酒酿造、贮存过程中的重要反应之一。该文对美拉德反应的机理、其产物对绍兴酒风味等的影响以及影响因素进行了简单的介绍和剖析。     

美拉德反应产物中三类官能团化合物的质量分布与主体香气特征

以葡萄糖、果糖、木糖和脱氧核糖4种糖类和20种氨基酸为原料,在维持碱性的条件下制备美拉德反应产物,并通过气相质谱(GC/MS)进行检测,分析杂环类、芳香族类和烯酮(醛)类三类官能团化合物作为美拉德反应产物中的关键组分,并获得其质量分布。通过感官评价描述了美拉德反应产物的主体香气特征,并对其主体香气进行评分。结果表明:不同糖类美拉德反应产物中,三类官能团化合物总质量的顺序依次为果糖、木糖、葡萄糖和脱氧核糖美拉德反应产物。不同氨基酸美拉德反应产物中,亮氨酸、赖氨酸和苯丙氨酸美拉德反应产物的三类官能团化合物总质量较高且主体香气评分也较高。大多数美拉德反应产物中三类官能团化合物的总质量对主体香气评分具有较好的关联度。但含硫氨基酸美拉德反应产物比较独特,其主体香气评分与产物中含硫化合物的分子结构形态密切相关。通过对美拉德反应产物中三类官能团化合物的质量分布和主体香气特征的研究,可以更好地掌握和应用美拉德反应产物。     

超声促进美拉德反应对金带细鲹鱼肉蛋白酶解物的修饰及潜在危害物形成的影响

本文采用超声波法促进金带细鲹鱼肉蛋白酶解物与葡萄糖间的美拉德修饰反应,研究美拉德反应对酶解物功能特性、抗氧化性及潜在危害物形成的影响。结果表明:超声功率或反应时间越高,修饰产物中游离氨基含量越低,接枝度越大,超声处理能加快美拉德反应的速率,且减少丙烯酰胺等美拉德反应潜在危害物的形成。功能特性分析表明,超声处理能显著提高酶解物的溶解性和乳化性(p0.05),同时,体外模拟消化分析表明,超声处理降低了酶解物的消化性。修饰产物的DPPH自由基清除力、羟自由基清除力、还原力和Fe~(2+)螯合力显著提高(p0.05),而且超声修饰的能力和修饰物的特性均优于水浴法处理组。超声波促进美拉德修饰反应可提高金带细鲹鱼肉蛋白酶解物的功能特性和抗氧化活性,并减少丙烯酰胺等美拉德反应潜在危害物的形成。     

糖对谷氨酰胺转氨酶交联米渣蛋白美拉德反应产物结构与功能的影响

将不同相对分子质量的核糖、葡萄糖、乳糖、阿拉伯胶与谷氨酰胺转氨酶(transglutaminase,TG)交联的米渣蛋白(rice dreg protein,RDP)进行美拉德反应,并分析美拉德反应产物(Maillard reaction products,MRPs)的结构、功能特性。结果表明:不同相对分子质量的糖与TG交联RDP在美拉德反应过程中,随着反应的进行,接枝度、褐变度及体系的p H值有明显变化,其中核糖和葡萄糖的变化最为明显,其次是乳糖、阿拉伯胶。结构上,核糖最易与TG交联RDP中赖氨酸和精氨酸自由氨基发生反应;功能性质上,MRPs的溶解性和乳化特性较原TG交联RDP都得到了不同程度的改善,从强到弱依次是核糖、葡萄糖、乳糖、阿拉伯胶。所有样品的流变学特性都表现出假塑性流体所特有的剪切变稀现象,葡萄糖和核糖的MRPs表观黏度较原TG交联RDP大,乳糖和阿拉伯胶的MRPs的表观黏度则较原TG交联RDP小。     

Structure and functional properties of rice protein–dextran conjugates prepared by the Maillard reaction

Dextran was grafted on to rice protein (RP) by the wet‐heating Maillard reaction, and the structure and functional properties of the rice protein–dextran conjugates (RPDCs) were investigated. The RPDCs obtained by the Maillard reaction exhibited superior functionality compared with original RP. The solubility, emulsifying activity index, emulsifying stability index, foaming activity index and foaming stability of the RPDCs increased by factors of 7.50, 1.79, 2.20, 1.69 and 2.01, respectively, compared to original RP. The molecular weight, particle size distribution, surface hydrophobicity, secondary structures, amino acid compositions and chemical bonds of RPDCs were also characterised. The structure–function relationship was preliminary discussed, and the relationship suggests that the improvements in the functional properties were closely related to structural changes.     

响应面分析法在米渣水解蛋白-麦芽糊精Maillard反应物乳化特性研究中的应用

通过二次回归通用旋转正交试验设计,应用响应面分析法对米渣水解蛋白-麦芽糊精(RRHP-MD)Maillard反应过程中的各反应条件进行分析,建立数学模型,优化反应条件参数,以求得到乳化活性(EA)佳的RRHP-MDMaillard反应共聚物。结果表明:在58℃,采用水解度(DH)为6的RRHP,保持其与MD的比例为8:1,pH为6.5,反应3d可以得到高乳化活性的反应共聚物。在此最佳反应条件下对反应共聚物的乳化活性进行了研究,证实了预测值和实测值是一致的。此时,反应物乳化活性比国外进口的酪朊酸钠还要好。     

Functional Properties of Water-soluble Proteins from Silver Carp (Hypophthalmichthys molitrix) Conjugated with Five Different Kinds of Sugar

Water-soluble proteins (WSP) from silver carp denature easily during thermal processing, leading to the reduction of functional properties. In order to improve the functional properties of WSP and to utilize its resources efficiently, five different kinds of sugars (i.e., xylose, glucose, galactose, oligo-isomaltose, and dextran-10) were used to conjugate with WSP by Maillard reaction. Results suggested that the use of the Maillard reaction improved the solubility, heat stability, and emulsifying properties of WSP. With the increase of molecular weight (MW) of the sugars, the solubility, emulsifying properties, and total sulfhydryl (SH) groups of WSP increased, while the surface hydrophobicity decreased. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of the five Maillard reaction products (MRPs) showed that xylose reacted easily with WSP than did the other four kinds of sugar. Dextran-10 conjugated to WSP could efficiently improve the functional properties of WSP during heat processing.