Viscosity of guar gum and xanthan/guar gum mixture solutions

The viscosity of diluted guar gum solutions and the viscosity of xanthan and guar gum mixture solutions have been studied. Guar gum solutions showed pseudoplastic behaviour. Apparent viscosity increased with gum concentration and decreased with the temperature at which viscosity was measured. A maximum in the plot of viscosity versus increasing dissolution temperature was observed at 60 °C. This behaviour was related to differences in molecular structure of the polymers solved at different temperatures. Mixtures of xanthan and guar gum showed a higher combined viscosity than that occurring in each separate gum. This synergistic interaction was affected by the gum ratio in the mixture and dissolution temperature of both gums. The effect of polysaccharide concentration (1.0, 1.5 and 2.0 kg m⁻³), xanthan/guar gum ratio (1/5, 4/2, 3/3, 4/2 and 5/1) and dissolution temperature (25, 40, 60 and 80 °C for both gums) on the viscosity of solutions of mixtures were studied. The highest viscosities were observed when 2.0 kg m⁻³ gum concentration was used together with a ratio of xanthan/guar gum of 3/3 (w/w) and dissolution temperature of 40 and 80 °C for xanthan and guar gum, respectively. © 2000 Society of Chemical Industry     

瓜尔胶和黄原胶对马铃薯淀粉糊化特性影响的比较研究

将马铃薯淀粉分别与瓜尔胶和黄原胶以一定的比例复配,探讨两种胶体对马铃薯淀粉黏度、热稳定性、凝沉性、冻融稳定性和质构特性等糊化特性的影响。结果表明:瓜尔胶提高了淀粉糊的黏度和冻融稳定性,降低了淀粉糊的热稳定性、凝沉性、硬度、黏附性、胶黏性和咀嚼性;而黄原胶增加了淀粉糊的热稳定性和冻融稳定性,但降低了糊的黏度、凝沉性、硬度、黏附性、胶黏性和咀嚼性;且随着两种胶体含量的不同淀粉糊化特性也不同。      

刺槐豆胶/瓜尔豆胶复合体系的流变学性质研究

研究刺槐豆胶(LBG)/瓜尔豆胶(GG)复合体系的流变学性质,并采用流变学的模型进行拟合分析。实验表明:BG/GG复合体系为非牛顿流体,流动曲线服从Carreau模型,随着LBG比例的增大,其粘度越小,非牛顿性越不明显,触变性越低。LBG与GG复配对粘度的影响可产生协同作用,LBG/GG=1∶9时,复合体系粘度最大。在频率扫描范围内,LBG/GG复合体系同时具有粘性和弹性,随不同的角频率处理展现不同的动态粘弹性行为,LBG/GG=1∶9时,复合体系的动弹粘弹性最大。      

降解黄原胶与降解瓜胶凝胶体系的流变性研究

降解黄原胶与降解瓜胶在一定条件下共混,形成凝胶体系.通过对其流变特性进行研究,表明该体系具有显著的黏弹性和剪切变稀性.考察了总胶浓度、蔗糖、共混比例及降解食品多糖的分子量等因素对共混凝胶体系流变特性的影响.研究了该凝胶体系的本构方程,结果表明,修正Williamous-Oldroyld-4参数模型可确切描述凝胶体系的黏度曲线,计算值与实验值吻合良好.     

Effect of guar gum on the rheological, thermal and textural properties of soybean β-conglycinin gel

The effect of guar gum, a non-gelling neutral polysaccharide, on the thermal gelation of soybean β-conglycinin was analysed using the dynamic oscillatory rheological measurement, differential scanning calorimetry and texture profile analysis. The endothermic peak temperature of β-conglycinin in the presence of 0.5% guar gum was about 89.1 °C. However, the endothermic peaks shifted to higher temperatures as the guar gum concentration increased from 0.05% to 0.5%, which could be attributed to the thermodynamic incompatibility with guar gum, resulting in a promoted aggregation of the thermally denatured β-conglycinin. Furthermore, the elastic modulus increased with increasing concentration of guar gum, with a less frequency dependence. In addition, the springiness, cohesiveness and fracturability enhanced but the hardness decreased, as the guar gum concentration increased. The study demonstrated that incorporation of guar gum improved markedly the thermal and functional properties of soybean β-conglycinin thermal-induced gel, which can help better to design new food formulations.     

Effects of guar gum and arabic gum on the physicochemical,sensory and flow behaviour characteristics of frozen yoghurt

This study investigated the effect of guar gum and arabic gum on physicochemical, sensory and flow behaviour properties of frozen yoghurt. The results indicated that gums significantly affected the viscosity, overrun and melting rate of frozen yoghurt. The highest overrun value was observed in sample containing 0.5% arabic gum. Frozen yoghurt containing 0.3% guar gum had the highest viscosity. The longest first dripping time was observed in sample containing 0.5% arabic gum. Flow behaviour of samples showed that all frozen yoghurts exhibited shear thinning behaviour. Guar gum at a concentration of 0.2% and arabic gum at a concentration of 0.5% presented the best total acceptability. The results of this study revealed that the frozen yoghurt produced with arabic gum had the better overall sensory and physicochemical characteristics.     

不同浓度阴离子瓜尔胶溶液的流变特性研究

采用AR-G2流变仪,通过稳态流动、应变扫描、频率扫描及动态黏弹性温度扫描等实验详细研究了瓜尔胶溶液浓度对其流变特性的影响,并从微观结构上进行解析。实验得到的各个流变特性参数与浓度之间存在高度相关性,通过数理统计分析,对上述相关性进行拟合并得到一系列方程。     

The effect of guar gum in solution on diffusion of cholesterol mixed micelles

A technique was developed to measure the diffusion of cholesterol mixed micelles through solutions of guar gum. By incorporating β-carotene in the micelles it was possible to make the suspension visible using the yellow colour for spectrophotometric quantification and to gauge the extent of diffusion. The results showed a rapid reduction in rate of diffusion with increase in guar gum concentration until above 0.2% the rate became constant and extremely slow.     

Viscosity of solutions of xanthan/locust bean gum mixtures

Xanthan and locust bean gums are polysaccharides able to produce aqueous solutions with high viscosity and non‐Newtonian behaviour. When these solutions are mixed a dramatic increase on viscosity is observed, much greater than the combined viscosity of the separated polysaccharide solutions. In this work the influences of different variables on the viscosity of solutions of mixtures of xanthan/locust bean gum have been studied. Total polysaccharide concentration, xanthan and locust bean ratio on mixture and temperature at which the gum was dissolved (dissolution temperature) for both xanthan and locust bean gums have been considered. Under these different operational mixture conditions shear rate and time have also been considered to describe the rheological behaviour of the solutions studied. The high viscosity increase observed in these mixtures is due to the interaction between xanthan gum and locust bean gum molecules. This interaction takes place between the side chains of xanthan and the backbone of the locust bean gum. Both xanthan molecule conformation in solution – tertiary structure – and locust bean gum structure show great influence on the final viscosity of the solution mixtures. Xanthan conformation changes with temperature, going from ordered structures to disordered or chaotic ones. Locust bean gum composition changes with dissolution temperature, showing a dissolved galactose/mannose ratio reduction when temperature increases, ie the smooth regions – zones without galactose radicals – are predominantly dissolved. The highest viscosity was obtained for the solution mixture with a total polysaccharide concentration of 1.5 kg m⁻³ and a xanthan/locust ratio of 2:4 (w/w) and when xanthan gum and locust bean gum were dissolved at 40°C and 80°C, respectively. © 1999 Society of Chemical Industry     

低黏度瓜尔胶的制备及其增强性能研究

以双氧水为氧化剂,对羟丙基瓜尔胶进行氧化降解,使其黏度从2390mPa·s降到10mPa·s以下。将降解后的瓜尔胶对滤嘴棒纸进行涂布,研究其增强性能,考察其对纸张抗张指数、裂断长、撕裂度、耐破度和耐折度的影响。得出低黏度瓜尔胶氧化降解的较佳工艺为:密封,过氧化氢用量为8.6%、反应温度65℃、反应时间4h。选出效果较优的低黏度羟丙基瓜尔胶,研究涂布浓度和涂布温度对其增强性能的影响。最后将制备的低黏度瓜尔胶与改性淀粉对滤嘴棒纸的增强性能做了比较。     

瓜尔豆胶对搅打稀奶油的搅打性能的影响

研究了不同浓度的瓜尔豆胶对搅打稀奶油乳状液的表观黏度、脂肪球粒度、脂肪球界面蛋白浓度、脂肪球部分聚结率、泡沫硬度和搅打起泡率的影响。结果表明，瓜尔豆胶对搅打稀奶油乳状液的表观黏度影响非常显著；瓜尔豆胶浓度过高或过低，都会使得解冻后的乳状液粒径变大；瓜尔豆胶的质量分数越高，脂肪球部分聚结速度越快，泡沫硬度也越大；搅打起泡率随着瓜尔豆胶质量分数增大而降低。     

Oleogel production based on binary and ternary mixtures of sodium caseinate,xanthan gum,and guar gum: Optimization of hydrocolloids concentration and drying method

We report the optimization of oleogel formulation based on sodium caseinate (CN, 0–4 g/100 g), xanthan gum (XG, 0–1 g/100 g), guar gum (GG, 0–1 g/100 g), and drying method (freeze and oven drier) using response surface methodology to achieve the desired oil binding capacity, textural, and rheological attributes. All the selected responses were successfully fitted by a quadratic model with determination coefficient values higher than .95 with the exception of firmness values which was fitted by linear model. There were considerable increases in all the responses for the samples containing ternary mixtures of protein-gum (CN:XG:GG) as well as binary mixtures (CN:GG and CN:XG) compared to samples containing protein or gums alone due to the synergistic effect of CN and gums on formation of highly ordered and strong gel network. Regression modeling demonstrated that freeze drying method led to significantly greater structure recovery values than those of oven drying method. The best formulation was the freeze dried oleogel containing 4 g/100 g CN, 0.43 g/100 g XG, and 0.98 g/100 g GG. Results showed that fabrication of oleogels with at least 94.5 g/100 g sunflower oil and characteristics similar to industrial shortening is feasible.     

Rheological behaviour of tamarind seed gum in aqueous solutions

Tamarind seed gum as seed polysaccharide from Tamarindus indica L. has been characterized for physicochemical and rheological properties in the present work. The structural analysis determined the presence of glucose:xylose:galactose in a molar ratio of 2.61:1.43:1.The Huggins and Kraemer plots obtained by capillary viscometry gave an intrinsic viscosity of 4.7 dl g⁻¹ and the viscosity average molecular mass was calculated to be 9.18 × 10⁵ g mol⁻¹ using the Mark-Houwink relationship. The steady shear and dynamic viscoelasticity properties of tamarind seed gum in aqueous solutions at different concentrations were investigated at 20 °C using a Haake Rheometer RS75. The tamarind seed gum solutions clearly exhibited shear-thinning flow behaviour at high shear rate and Newtonian region occurred at low shear rate range, however, at higher concentrations, pronounced shear thinning was observed. The value of zero shear viscosity (η₀) was estimated by fitting Cross and Carreau models. The specific viscosity at zero shear rate (η_sp0) was plotted against the coil overlap parameter (C[η]) and the slopes of the lines in the dilute and semi-dilute regions were found to be ∼2.2 and 4.3, respectively. The value of the critical concentration (C^∗) was about 4.23/[η]. While, the mechanical spectra in the linear viscoelastic region of tamarind seed gum solutions showed the typical shape for macromolecular solutions. Plots of η versus γ and η^∗ versus ω were superimposable and hence obey the Cox-Merz rule.     

瓜尔胶对木薯淀粉消化性、糊化特性、水分运动性的影响

研究瓜尔胶对木薯淀粉消化性的影响,采用Englyst法测定淀粉的消化性,比较与分析了瓜尔胶/木薯淀粉体系的糊化特性、水分运动性、微观结构的差异,从而探究瓜尔胶对木薯淀粉消化性的影响机理。结果表明:瓜尔胶添加量较低时,糊化后冷却至37℃的体系结构疏松、具有较高的水分运动性,瓜尔胶促进淀粉的酶解,抗消化淀粉含量较低;继续提高瓜尔胶添加量时,糊化后冷却至37℃的体系结构越加紧密、水分运动性降低,瓜尔胶形成空间位阻,降低酶与底物的可及性,瓜尔胶反而抑制淀粉的酶解,抗消化淀粉含量较高。      

刺云实胶与黄原胶复配体系质构及流变性研究

将总浓度为1%的刺云实胶(TG)与黄原胶(XTG)按照不同的质量比复配,采用质构仪和流变仪对复配体系的凝胶特性和流变学特性进行测定,通过Carreau模型对流动曲线进行拟合分析,并利用电子扫描显微镜分析复配体系网络形成机理。结果表明:在质构分析中TG与XTG质量比为64时有最大的凝胶强度;在流变分析中TG与XTG质量比为64时呈现最大表观黏度并且在频率扫描和温度扫描中表现出最大的储能模量(G′)。因此,TG与XTG的最佳复配比例为质量比64。在pH为5～10时,最佳复配比例体系的黏度保持相对稳定;当添加盐离子(Na+、Ca2+)后,体系黏度降低,Ca2+降低的趋势更为显著。通过电子扫描显微镜(SEM)分析,表明在TG与XTG之间存在明显的协同增效作用,可形成良好的凝胶网络结构。     

阳离子瓜尔胶的制备及其助留助滤性能

以瓜尔胶原粉为原料,3-氯-2-羟丙基三甲基氯化铵(CTA)为阳离子醚化剂,分别在4种离子液体中制备了4种阳离子瓜尔胶(CGG)。经测定,在离子液体[AMIM]Ac中合成的阳离子瓜尔胶具有最高的氮质量分数。利用正交实验和单因素实验考察了醚化剂用量、反应温度、反应时间、碱化时间、碱用量对产物氮质量分数及黏度的影响,确定了优化合成条件。经测定,产物的氮质量分数为1.95%,黏度为583 mPa·s。对比发现,在[AMIM]Ac中合成的阳离子瓜尔胶较在乙醇和异丙醇中合成的阳离子瓜尔胶具有更高的氮质量分数和黏度,说明离子液体对瓜尔胶的醚化反应起到一定的保护作用。对比不同取代度和在不同溶剂中合成的阳离子瓜尔胶对脱墨废纸浆的细小组分单程留着率(FPR)发现,CGG-5的助留效果最好(CGG-5用量为0.06%,FPR为72.3%)。     

A comparative study on viscosity behavior of water‐soluble chemically modified guar gum derivatives with different functional lateral groups

A comparative study was carried out on the viscosity behavior of three new water‐soluble chemically modified guar gum derivatives with different functional lateral groups, including O‐carboxymethyl‐O‐hydroxypropyl guar gum (CMHPG), with anionic character, O‐2‐hydroxy‐3‐(trimethylammonio)propyl guar gum (HTPG), with cationic character, and O‐carboxymethyl‐O‐2‐hydroxy‐3‐(trimethylammonio)propyl guar (CMHTPG), with amphoteric character. It was found that the shear rate, concentration, temperature, added salt and surfactant affected the viscosity properties of these new guar gum derivatives in aqueous solutions. Regardless of the functional lateral groups, all sample solutions behaved as non‐Newtonian shear‐thinning fluids, and their viscosity increased with the increase in their concentration but decreased with the increase in temperature. Aqueous CMHTPG solution had the strongest shear‐thinning property, and aqueous CMHPG solution investigated had the greatest viscous flow activation energy. In contrast to cationic HTPG or anionic CMHPG, amphoteric CMHTPG had an enhanced viscosity property in aqueous salt solutions, exhibiting an unusual anti‐polyelectrolyte viscosity behavior. The addition of sodium dodecylsulfate was found to result in a decrease in the viscosity of aqueous HTPG solution and an increase in the viscosity of aqueous CMHPG solution or CMHTPG solution. Copyright © 2005 Society of Chemical Industry     

变性淀粉和瓜尔豆胶在速冻包子面皮中的应用研究

包子面皮中加入保水剂可以减少冷却贮藏过程中的水分和风味流失。本实验以鸡肉和其他原料为馅料,根据对面皮质量的不同需求选择三种较合适的变性淀粉,并以质构、色泽、失水率为指标对其添加量以及瓜尔豆胶添加量分别进行单因素和正交实验。结果表明:六种变性淀粉中木薯交联羟丙基淀粉的冻融稳定性最好,糯玉米羟丙基淀粉的热稳定性最好,木薯预糊化淀粉的回生值最低,单因素实验确定糯玉米羟丙基淀粉最佳添加量为2%,瓜尔豆胶添加量为0.3%。正交实验结果为使用糯玉米羟丙基淀粉,添加量4%,瓜尔豆胶添加量0.3%,此组合的质构指标综合评分为最高值3.04,L值为61.88,失水率为0.55%。      

Rheological/textural properties of starch and crude hsian‐tsao leaf gum mixed systems

The Effects of hsian‐tsao leaf gum (HG) on the rheological/textural properties of non‐waxy starches were studied. Pronounced interactions between starch and HG were observed. The rheological properties, including pseudo‐gel viscosity in the rapid visco‐analyser test, storage and loss moduli in the dynamic rheological test, as well as firmness in the texture analyser test, of the mixed gels generally improved with increasing gum concentration to a certain level, then deteriorated with further increase in gum concentration. The critical gum concentration for the development of optimal rheological properties depended on the starch type and concentration. Within the concentration range studied, mixed systems with wheat starch could generally reach the highest pseudo‐gel viscosity, firmness, and storage modulus if the starch/HG ratio was appropriate, followed by those with corn and tapioca starch. Copyright © 2003 Society of Chemical Industry