酸性条件下低酯果胶对酪蛋白酸钠流变特性及微观结构的影响

以酪蛋白酸钠为原料,在pH值为4.0,质量浓度为4 g/100mL的酪蛋白酸钠中分别添加0、0.3、0.6、0.9、1.2、1.5 g/100mL的低酯果胶,考察低酯果胶对酪蛋白酸钠溶液流变特性及微观结构的影响。结果表明,低酯果胶对酪蛋白酸钠溶液的流变特性有较大影响。随着低酯果胶添加量的增加,复合体系流体指数n下降,稠度系数K逐渐增大,表现出典型的假塑性流体的特征,在1.5 g/100mL的添加量时,体系黏弹性表现为最佳。Zeta电位以及粒径大小的结果表明,随着果胶的加入体系多糖与蛋白质间静电吸引力增大,果胶吸附层厚度增大,复合物平均粒径增大。微观结构观察发现,体系结构随着果胶浓度的增大,从球形蛋白簇结构变成分支较细且致密的网状结构,当果胶加入量达到1.5 g/100mL时,体系固性特征最为明显。     

添加酪蛋白酸钠对低脂乳化香肠食用品质的影响

本研究测定不同添加量的酪蛋白酸钠(0、0.5%、1.0%、1.5%、2%)对各组乳化香肠保水性、蒸煮损失、色泽、p H、感官品质和质构特性等食用品质的影响。结果表明:添加酪蛋白酸钠组与对照组(酪蛋白酸钠添加量0)的保水性、蒸煮损失、色泽、感官品质和质构特性存在显著差异(p0.05),而p H无显著差异(p0.05)。随着酪蛋白酸钠添加量的增加,保水性、硬度、胶黏性、胶着性、咀嚼性和感官得分显著提高,亮度(L*)和蒸煮损失显著降低。酪蛋白酸钠添加量为1.5%的样品组,香肠保水性、硬度、胶黏性、胶着性、咀嚼性和感官评定得分最高,蒸煮损失最小,添加1.5%的酪蛋白酸钠可作为脂肪替代品在肉制品中推广应用。     

蛋白质强化对发酵乳品质和风味特性的影响

为了探究蛋白质强化对发酵乳品质特性及挥发性风味物质的影响,使用酪蛋白酸钠、浓缩乳清蛋白和乳蛋白浓缩物对发酵乳进行强化.结果表明:3种蛋白强化均会减低发酵速率,在对发酵乳的质构特性影响方面酪蛋白酸钠能大幅提高发酵乳的硬度、黏力、弹性和胶着性,浓缩乳清蛋白最能提高发酵乳的弹性模量、黏性模量,而乳蛋白浓缩物的影响均介于酪蛋白...     

不同类型蛋白原料对类夸克乳制品质构及稳定性的影响

文章研究了浓缩牛乳蛋白(MPC)、热稳定性浓缩乳清蛋白(WPC)、酪蛋白酸钠和全脂乳粉(WMP)4种蛋白原料对类夸克乳酪质构、持水性和流变等方面的影响。实验结果表明,在硬度、黏性上酪蛋白酸钠组最高,其次是WPC组,而MPC和WMP组差异不显著;在内聚性上,MPC组最低,其次是酪蛋白酸钠组,MPC和WPC组最高且差异不显著;各组样品在持水性上表现出的趋势与内聚性相同。WPC组的抗剪切能力最强,酪蛋白酸钠组最弱;MPC组抗剪切能力也较佳,但黏度始终是最低的。总体来说,要制得较佳的类夸克乳制品,建议以酪蛋白酸钠和MPC为主,并根据所需达到效果混合其他原料使用。     

花生ACE抑制肽结构表征与构效关系

为生产富含血管紧张素转换酶（Angiotensin-I converting enzyme,ACE）抑制肽发酵乳,使用酪蛋白酸钠和高产ACE抑制肽菌株植物乳杆菌M11（Lb. plantarum M11）对发酵乳进行强化。以酪蛋白酸钠添加量、接种量及发酵温度作为考察因素,在单因素实验的基础上进行三因素三水平的响应面试验,以获得富含ACE抑制肽发酵乳的最佳生产工艺条件,并探讨了酪蛋白酸钠和Lb. plantarum M11对发酵乳质构特性和风味特性的影响。结果表明：当酪蛋白酸钠添加量为2%、接种量为1.5×10⁷ CFU/mL,发酵温度为40 ℃时,发酵乳的ACE抑制活性最高,为83.15%。添加Lb. plantarum M11和酪蛋白酸钠的发酵乳硬度、稠度、粘聚性和粘度指数都显著提高（P<0.05）,质构特性最好。电子舌分析结果显示,Lb. plantarum M11的添加增强了发酵乳的酸味和丰富性,Lb. plantarum M11和酪蛋白酸钠对咸味、苦味、涩味、涩味回味、苦味回味以及鲜味都没有明显影响。本研究为开发具有降血压活性的功能性发酵乳提供了理论依据。     

果胶-酪蛋白酸钠纳米复合物的特性

以果胶、酪蛋白酸钠为原料,在一定条件下制备果胶-酪蛋白酸钠纳米粒子复合物,对复合物特性进行表征。结果表明,随着pH (3.0～8.0)增大,果胶-酪蛋白酸钠复合物的带电量从-10.2 mV降低到-48.6 mV。pH在3.0～5.0范围内粒径较小,均在300 nm以下,都是单峰,其粒径分布较集中。果胶-酪蛋白酸钠复合物表面疏水性在pH 4时为26.5μg,羰基含量为5.3μmol/g,均比酪蛋白酸钠的高,而游离巯基含量为6.2μmol/g,这为果胶-酪蛋白酸钠复合物的进一步利用提供理论依据。     

添加酪蛋白酸钠对低脂乳化香肠食用品质的影响

本研究测定不同添加量的酪蛋白酸钠(0、0.5%、1.0%、1.5%、2%)对各组乳化香肠保水性、蒸煮损失、色泽、p H、感官品质和质构特性等食用品质的影响。结果表明:添加酪蛋白酸钠组与对照组(酪蛋白酸钠添加量0)的保水性、蒸煮损失、色泽、感官品质和质构特性存在显著差异(p<0.05),而p H无显著差异(p>0.05)。随着酪蛋白酸钠添加量的增加,保水性、硬度、胶黏性、胶着性、咀嚼性和感官得分显著提高,亮度(L*)和蒸煮损失显著降低。酪蛋白酸钠添加量为1.5%的样品组,香肠保水性、硬度、胶黏性、胶着性、咀嚼性和感官评定得分最高,蒸煮损失最小,添加1.5%的酪蛋白酸钠可作为脂肪替代品在肉制品中推广应用。      

酪蛋白酸钠的功能特性及其应用

酪蛋白酸钠的功能特性及其应用刘志皋，何涛（天津轻工业学院天津，３００２２２）酪蛋白酸钠亦称酪朊酸钠或酪蛋白钠，是酪蛋白和钠的加成化合物。它是用碱性物（如氢氧化钠）处理酪蛋白凝乳，将水不溶性的酪蛋白转变成可溶件形式所得到的一种白色或淡黄色颗粒或粉末。这...     

不同带电特性的壳聚糖/酪蛋白相互作用研究

为了建立多糖的带电特性与蛋白质复合体系的关系,以壳聚糖(CS)和酪蛋白为试验对象,通过荧光光谱法、紫外-可见吸收光谱法、傅里叶红外吸收光谱法及流变黏态分析法研究CS与酪蛋白的复合机制及流变特性.结果表明:荧光光谱中,CS对酪蛋白的猝灭方式是静态的.在温度303 K和313 K条件下,高脱乙酰度壳聚糖(HDCS)的结合位...     

盐及酪蛋白酸钠对藜麦面团及面条品质的影响

本文以藜麦面为研究对象,通过添加KCl、NaCl、酪蛋白酸钠以改善藜麦面团的性质,研究了不同处理条件对藜面团质的硬度、咀嚼性、黏度等质构特性以及储能模量、损耗模量、复合粘度等流变学特性的影响。结果表明:当添加的水量为50%藜麦面团成型的光滑程度、弹性较好;当藜麦面中加入1.5%酪蛋白酸钠+1% KCl所制备的藜麦面团粘性适中、硬度和弹性较好;NaCl、KCl、酪蛋白酸钠的加入,均可改善面团的G'、G'、黏度,1.5%酪蛋白酸钠+1% KCl加入,可增大藜麦面团的G'、G'、黏度;NaCl和酪蛋白酸钠都可以明显的改善藜麦面条吸水率,NaCl可降低藜麦面条的干物质损失率,KCl的作用与之相反,而酪蛋白酸钠与1% KCl联合使用,在增加其吸水率的同时减少了干物质损耗率,当同时添加2.0%酪蛋白酸钠和1% KCl条件下达到最适,而且恢复能力达到最佳;酪蛋白酸钠与1% KCl可增加藜麦面条表面片层的致密程度。因此,1.5%酪蛋白酸钠+1% KCl的添加量对藜麦面团的弹性、硬度、咀嚼性均达到最佳,同时添加2.0%酪蛋白酸钠和1% KCl能显著（P<0.05）改善藜麦面条的蒸煮损失及干物质损失率,降低面汤浊度,还可以增加藜麦面条的硬度,从而增加其咀嚼性。     

发酵液中威兰胶的乙醇沉淀行为

作者研究了发酵液中威兰胶在乙醇溶剂作用下的沉淀行为,分析了乙醇质量浓度、pH值、盐离子种类和盐浓度等因素对威兰胶沉淀效果的影响,以及对沉淀物最终产物流变学性能的影响。确定威兰胶的最佳沉淀条件为:当添加2.5mol/LCaCl2溶液使威兰胶发酵液中的最终电荷浓度达到0.1mol/L,pH调至2.0,乙醇质量浓度为37.6g/dL时,可以有效沉淀分离得到威兰胶,收率为92.5%,并保持良好的流变学性能,比对照条件下的乙醇用量节省了73.3%。     

Physicochemical changes in surimi with salt substitute

Protein endothermic transitions (thermal denaturation), rheological properties (protein gelation), and fundamental texture properties (shear stress and strain at mechanical fracture) of Alaska pollock surimi gels made with 0 (control), 1, 2, and 3 g/100 g of salt (NaCl) were determined and compared with equal molar concentration of salt substitute. Salt and salt substitute shifted the onset of myosin transition to higher temperature and resulted in larger myosin peaks (i.e., transition enthalpy). Endothermic transitions showed similar trends to rheological properties. The elastic modulus (G′) increased when salt or salt substitute was added to surimi, except at the highest concentration of salt and salt substitute. Salt and salt substitute also induced the onset of protein gelation (i.e., as measured by significant increase of G′) at lower temperature. Surimi gels with salt substitute and salt at equal molar concentrations had similar texture properties (shear stress and strain). Based on the present study, salt substitute can be used in the development of low-sodium surimi seafood products without significant change in gelation and texture.     

Effect of salt content on the rheological properties of salad dressing-type emulsions stabilized by emulsifier blends

The effects that salt content and composition of emulsifier blends exert on the rheological properties of salad dressing-type emulsions were studied. Binary blends of egg yolk and different types of amphiphilic molecules (Tween 20, sucrose laurate and pea protein), in several proportions, were used to stabilize emulsions. Salt concentration was ranged from 0 to 2.3% w/w. Steady-state flow tests and small-amplitude oscillatory shear measurements within the linear viscoelastic region were carried out. Rheological tests were complemented with droplet size distribution measurements. Rheological properties and physical stability of the emulsions studied were significantly influenced by salt content and the nature of binary emulsifier blends. In general, the values of rheological parameters studied increased with salt content. However, salt affects in much higher extent the properties of emulsions stabilized by high proportions of egg yolk or pea protein in the emulsifier blend, rather than those mainly stabilized by non-ionic low-molecular-weight surfactants, which are less sensitive to changes in the ionic strength. In this sense, the increase observed in the values of viscosity and linear viscoelastic functions of emulsions is more important when a protein is predominant in the emulsifier blend. This effect was explained on the basis of a more apparent increasing interdroplet interactions and viscosity of the continuous medium, both of them induced by salt addition, which lead to the consecution of an extensively flocculated state and improved creaming stability. On the contrary, different blends of pea protein and egg yolk showed a quite similar evolution of the rheological parameters with salt concentration.     

Rheological characterization of hair shampoo in the presence of dead sea salt

In Jordan, a growing industry has been established to produce different types of Dead Sea (DS) cosmetics that have DS salt (contains mainly NaCl, KCl, and MgCl(2)) in their formulas. In this work, the effect of DS salt on the rheology of hair shampoo containing the sodium lauryl ether sulfate as a main active matter was studied. The effects of DS salt and active matter concentration, and the temperature and time of salt mixing, on the rheological properties of hair shampoo were investigated. The salt-free shampoo showed a Newtonian behavior at 'low active matter' (LAM) and shear thinning at 'high active matter' (HAM). The presence of DS salt changed the rheological behavior of LAM shampoo from Newtonian (for the salt-free shampoo) to shear thinning. On the other hand, the behavior of HAM shampoo switched from shear thinning to Newtonian behavior in the presence of high concentration of DS salt. The addition of DS salt increased the apparent viscosity of shampoo to reach a maximum value that corresponded to a salt concentration of 1.5 wt.%. Further addition of DS salt led to a decrease in the shampoo viscosity to reach a value less than that of the salt-free sample at high salt concentration. Changing the mixing temperature (25-45 degrees C) and mixing time (15-120 min) of DS salt with shampoo has no significant influence on the rheological behavior. However, the mixing process increased the apparent viscosity of salt-free shampoo. The power law model fitted well the flow curves of hair shampoo with and without DS salt.     

Reducing salt level in food: Part 1. Factors affecting the manufacture of model cheese systems and their structure–texture relationships

A model lipoproteic matrix able to mimic hard-type cheese was produced with controlled structural and textural properties. Changes in the microstructural and rheological properties of these model cheeses made from different milk concentrate powder, anhydrous milk fat, salt contents and pH values at renneting were characterised. Rheological properties were measured by texture profile analysis, fat globule and protein aggregate size distributions by laser light scattering. Microstructural properties of the model matrices were studied by confocal laser scanning and scanning electron microscopy.Significant differences between the matrices were found for the structural, physico-chemical and rheological parameters measured. Cheeses with higher dry matter content were significantly harder and contained more insoluble proteins than cheeses with lower dry matter content. The salt concentration and the pH at renneting had significant influence on cheese hardness and adhesiveness of rheological parameters. The model lipoproteic matrix presented air bubbles and powder aggregates which could not be avoided during the manufacture of products. However, compared with classic cheese making with rennet or acid coagulation, the technology used here allows model cheeses to be produced rapidly with a good reproducibility of texture.     

Effect of heating temperature and sodium chloride concentration on ultrastructure and texture of gels made from giant squid (Dosidicus gigas) with addition of starch,l-carrageenan and egg white

This paper seeks to compare the ultrastructure of gels made from frozen muscle of giant squid (Dosidicus gigas) at various temperatures with a number of different rheological parameters, with reference to a variety of added ingredients (non-muscle proteins and hydrocolloids) and to NaCl concentration. Interesting data on gel rheological properties were found where formulae containedl-carrageenan, starch and egg white, with a low salt concentration (1.5%). This seems to be because carrageenan forms an independent network which supports the principal structure formed by the fish protein; starch is incorporated into the network and retains water; and egg white forms a supplementary network which helps to improve rheological properties.     

Effect of heating temperature and sodium chloride concentration on ultrastructure and texture of gels made from giant squid (Dosidicus gigas) with addition of starch,l-carrageenan and egg white

This paper seeks to compare the ultrastructure of gels made from frozen muscle of giant squid (Dosidicus gigas) at various temperatures with a number of different rheological parameters, with reference to a variety of added ingredients (non-muscle proteins and hydrocolloids) and to NaCl concentration. Interesting data on gel rheological properties were found where formulae containedl-carrageenan, starch and egg white, with a low salt concentration (1.5%). This seems to be because carrageenan forms an independent network which supports the principal structure formed by the fish protein; starch is incorporated into the network and retains water; and egg white forms a supplementary network which helps to improve rheological properties.     

沙蒿籽胶的流变学性质研究

研究了沙蒿籽胶的静态流变学特性和动态流变学特性。静态流变学表明:沙蒿籽胶溶液是触变性流体,其表观粘度随质量分数的增加而增加,且随剪切速率变化的影响符合Herschel-Bulkey模型;温度、pH值等对沙蒿籽胶溶液的表观粘度影响较小;盐的加入能改变沙蒿籽胶溶液的粘度。动态流变学特性表明:沙蒿籽胶溶液显示弱凝胶特性。     

Preparation and Aqueous Properties of Starch‐grafted Polyacrylamide Copolymers

In the present work, starch‐grafted polyacrylamide copolymers were prepared and their rheological properties, either in water or in water‐based muds, were investigated. The advantages in using starches as substrates to prepare additives which are suited for improving stability and the rheological properties of water‐based muds, lie in their low cost, and their lower biodegradability than native starches. Thus, various copolymer series were prepared by free‐radically grafting acrylamide (AM) onto starch using ceric ammonium sulphate (CAS) as initiator. It is shown that the intrinsic viscosity and the molecular weight of the grafted starches are controlled by the initiator and monomer concentrations. Furthermore, to predict the behaviour of the samples under oil‐well conditions, the aqueous solution properties of the copolymers such as water solubility, viscosity, shear rate, were determined as function of temperature, salt concentration and type, and aging time. The knowledge of these properties is a prerequisite for the use of the copolymers in drilling fluids. The data indicate that starch‐grafted polyacrylamide copolymers as compared to the non‐modified starch, behave as shear‐thinning, are salt resistant, and their rheological properties are stable with time. The grafted starches as prepared above were also added to water‐based mud and the rheological properties of the resulting muds were determined under oil‐well conditions. Grafted starches, having high AM contents, are more efficient in decreasing the filtrate volume, and increasing the plastic viscosity of the muds, when compared to PAC‐L, a modified cellulosic polymer used in the filtration control of most water‐based muds. Such improvements in the rheological properties of the muds were found to result from the behaviour and/or properties of the grafted starches in water.     

DIELECTRIC PROPERTIES of STARCH SOLUTIONS AS INFLUENCED BY TEMPERATURE, CONCENTRATION, FREQUENCY and SALT

Dielectric properties of starch solutions (1 to 4% w/w) were evaluated at temperatures ranging from 20 to 80C at 10, 20 and 30 MHz. the effect of added salt (0.2 and 0.5% w/w) was investigated in relation to changes in trends exhibited by the relative permittivity, loss factor and penetration depth. the relative permittivity ranged from 46 to 308 and 65 to 92 for solutions with and without salt, respectively. the corresponding loss factor ranged 266 to 4133 and 9 to 266, respectively. Temperature, frequency, concentration and their interactions had different levels of significance on the dielectric properties of starch solutions. Salt enhanced the relative permittivity, and its effect conformed to the anomalous dispersion phenomenon. the loss factor increased with increasing temperature and salt content, and penetration depths associated with salt‐enriched samples were low compared to samples without salt. Generally, the effects of temperature, frequency, concentration and salt on the dielectric properties of starch solutions were attributed to the complex interaction between conductivity, density, moisture content, loss angle and starch rheological properties. Excellent correlations were developed that could be used for estimating the dielectric properties of starch solutions with and without salt.