Chemical Modification of Guaran Gum. Part 2: Cyanoethylation

Guar gum was cyanoethylated under a variety of conditions. It is shown that the extent of reaction increases by increasing the acrylo-concentration nitrile and decreases by increasing the reaction temperature. Cyanoethyl guaran pastes are characterized by non-Newtonian pseudoplastic behaviour and may be described by the power low T = kDⁿ in which the rheological parameters k and n depend mainly on the type of the derivatives. The apparent viscosity of these derivatives depends on its nitrogen content as well as the rate of shear.     

Chemical Modification of Guaran Gum Part I: Carboxymethylation in Aqueous Medium

Guar gum was isolated from the seeds and subjected to modification via carboxymethylation in aqueous medium. The modification increases its solubility in cold water, and increases the stability of its pastes to microorganisms. Regardless of the DS of these products, their aqueous solutions are characterized by non-Newtonian pseudoplastic behaviour, and their apparent viscosity at a constant rate of shear depends on the DS as well as the measuring temperature.     

Viscosity of locust bean (Ceratonia siliqua) gum solutions

Viscosity of locust bean (Ceratonia siliqua L) gum solutions has been studied. Shear rate, gum concentration and measuring and solubilisation temperatures were varied and the corresponding influences analysed. The gum solutions showed pseudoplastic behaviour. Apparent viscosity decreased with increasing measuring temperature. A maximum in the viscosity with increasing solubilisation temperature was observed, and it was assumed that this behaviour was related to differences in the molecular weight of the molecules dissolving at various temperatures, which produced a different galactose/mannose ratio in the solution. This effect was checked by a solubilisation study.     

压力协同温度控制天然阿拉伯胶的熟化改性研究

阿拉伯胶由于具有良好的溶解性、稳定性、乳化性等优异性能,被广泛的应用于生物、医药、食品和工业领域。以天然阿拉伯胶为研究对象,分别考察了压力、温度和处理时间对阿拉伯胶熟化的影响。结果表明,温度是阿拉伯胶熟化改性的主要影响因素,温度越高阿拉伯胶的平均分子量越大,在100℃条件下处理,12 h后平均分子量可达到2.8×107g/mol;超高压不能改变阿拉伯胶的熟化程度,但是能够明显的缩短熟化时间,提高改性效率;红外光谱检测结果表明,高压没有改变阿拉伯胶组分。试验结果将为天然阿拉伯胶的改性提供一种新的方法和途径。     

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     

响应面法优化桂皮胶的提取工艺

对高温高压条件下以水作为提取剂提取桂皮胶的工艺进行研究。在粉碎粒度、pH、料液比、提取温度、提取时间5个因素的单因素实验基础上,采用响应面分析法建立多元统计回归模型,考察桂皮胶提取过程中的四个主要影响因子即pH、料液比、提取温度、提取时间及其交互作用对提取量的影响。结果表明高压浸提法提取桂皮胶最佳工艺条件为pH5.0,料液比1:44(g/mL),提取温度125℃,提取时间31 min,在此最佳工艺条件下进行验证得到桂皮胶提取量为186.5 mg/g,与预测值187.1219 mg/g接近。桂皮胶提取物中总糖含量达到96.06%,采用此模型对桂皮胶提取量进行优化具有可行性。     

Isolation,Chemical Modification and Rheological Characterization of Leucaena Gum. Part I: Carboxymethylation

Leucaena gum was isolated from leucaena seeds and subjected to chemical modification via carboxymethylation under a variety of conditions. Variables studied include concentration of the etherifying agents and the preparation medium. It was found that the extent of carboxymethylation expressed as DS increases by increasing the concentration of the etherifying agents. Higher DS values were obtained in non-aqueous medium. The carboxymethylated leucaena derivatives are cold water soluble and can be precipitated by ethanol. Their pastes are characterized by non-Newtonian pseudoplastic behaviour regardless of the method of preparation or DS of the products. The apparent viscosity at various rates was thouroughly investigated. The effect of storing of these pastes on the rheological properties was also studied.     

糖基化提高大豆分离蛋白凝胶性的工艺条件

以提高大豆分离蛋白的凝胶强度为目的,采用添加D(+)木糖和黄原胶进行糖基化改性处理,中心组合设计模型对大豆分离蛋白共价改性工艺条件进行优化,测定并分析了改性复合物在各个条件下的凝胶强度。结果表明:适宜反应条件为反应温度87.27℃、反应时间40 min、复合糖添加量3.9%、糖胶比2.81∶1,此条件下凝胶强度可达到91.35 g,较未改性大豆分离蛋白提高78%。     

辣椒红色素改性和赋型的研究

为提高辣椒红色素的水溶性,采用混合乳化剂Tween60和单甘酯之比为1,对其进行物理改性,在色素粗品干重与混合乳化剂之比为1时,可以获得良好的乳化效果。经过物理改性后的色素水溶液可以用琼脂,阿拉伯胶等赋型剂进行赋型,获得粉末辣椒红色素,该品具有良好的水溶性。用金属钙,镁,锌的乙酸盐为络合剂分别对粗辣椒红色素进行化学改性,改性后的辣椒红色素的镁络盐和锌络盐易于干燥获得粉末产品。大大方便了辣椒红色素的干燥,包装,运输,储藏和使用,并可以提高辣椒红色素的应用范围和使用价值。     

The amino acid composition of the proteinaceous component of guar gum (Cyamopsis tetragonolobus)

Guar gum, powdered endosperm from the seeds of the legume Cyamopsis tetragonolobus, is a galactomannan which contains 2.5-4.5% of a proteinaceous component. Data presented for 11 bulk commercial samples show that the most abundant amino acids are glycine, glutamic acid, aspartic acid, serine and alanine, but that their relative proportions vary considerably. The proportions of other amino acids, e.g. histidine, isoleucine, phenylalanine, threonine, tyrosine and valine are remarkably constant. There appear to be some correlations between viscosity and the glycine, arginine and proline contents. Data for the amino acid compositions of several chemical derivatives of a medium-viscosity gum guar sample indicate that the proteinaceous component is retained but suffers variable modification. The amino acid profile for guar gum differs extensively from those for gum arabic and gum karaya; this provides a useful analytical supplement to sugar determinations for studies of admixtures of these hydrocolloids.     

Depletion Flocculation of Beverage Emulsions by Gum Arabic and Modified Starch

ABSTRACT: The creaming velocity, apparent viscosity, and ultrasonic attenuation spectra (1 to 50 MHz) of 5 wt% n hexadecane oil-in-water emulsions containing different droplet radii (r = 0.15 - 0.7 μm), biopolymer types (gum arabic or modified starch), and biopolymer concentrations (0 to 2.5 wt%) were measured. Depletion flocculation was observed in the emulsions when the nonabsorbed biopolymer concentration exceeded a critical concentration (CFC). The CFC increased with decreasing droplet radius for both biopolymers because the magnitude of the depletion attraction increases with droplet size. The CFC was lower for gum arabic than modified starch because it has a higher effective volume in solution. Depletion flocculation led to an increase in creaming instability and apparent viscosity of the emulsions. Flocculation could be nondestructively monitored by measuring the decrease in ultrasonic attenuation of the emulsions. These results show that depletion flocculation by gum arabic and modified starch can have an adverse effect on the stability of beverage emulsions.     

A Comparison of the Stability of Beverage Cloud Emulsions Formulated with Different Gum Acacia- and Starch-Based Emulsifiers

Abstract: The performance of several hydrocolloids (3 gum acacias, 1 modified gum acacia, and 3 modified starches) in stabilizing beverage emulsions and corresponding model beverages was investigated employing different core materials, emulsifier usage levels, and storage temperatures. Concentrated emulsions were prepared using orange terpenes or Miglyol^® 812 (comprising medium-chain triglycerides, MCT) weighted 1:1 with ester gum, stored at 25 or 35 °C, and analyzed on days 0, 1, and 3. On day 3, model beverages were made from each emulsion, stored at both temperatures, and analyzed weekly for 4 wk. Stability of concentrated emulsions was assessed by measuring mean particle size and by visual observations of ringing; beverage stability was judged similarly and also by loss of turbidity. Particle size measurements showed concentrated emulsions containing gum acacia or modified gum acacia with either core material were stable over 3 d storage at both temperatures whereas those made with modified starches were not, destabilization being faster at 35 °C. Beverages based on orange terpenes, in contrast to Miglyol, yielded smaller mean particle sizes, both on manufacture and during storage, regardless of hydrocolloid used. Visual observations of ringing generally supported this finding. Modified gum acacia was evaluated at both recommended and higher usage levels, stability increasing in the latter case. In general, all gum acacia and modified gum acacia emulsifiers were superior in stability to those based on modified starches, at either temperature, for orange terpene-based beverages. In Miglyol-based beverages, similar results were seen, except 1 modified starch performed as well as the gum acacia products.     

生物基吸附剂的研究现状与进展

综述了纤维素、淀粉、木质素、壳聚糖、果胶、瓜尔胶及农林废弃物等生物质材料及其衍生物在吸附领域的研究现状,根据被吸附物性质的差异,对不同生物质材料的改性方式及吸附性能进行分析和比较;结合当前生物基吸附剂的研究现状,提出了有待解决的问题,并对未来发展趋势进行展望,以推进生物基吸附剂的研究和发展。     

Adhesion of polysaccharides to intact cells and protoplasts of Nicotiana tabacum BY-2 and its stimulative effects on protoplast growth

The adhesion of water-soluble beta-d-glycans, including cellulose-adhesive schizophyllan, xyloglucan, and locust bean gum to intact cells and protoplasts of Nicotiana tabacum BY-2 was examined using their fluorescent derivatives. Fluorescence microscopy showed that schizophyllan, xyloglucan, locust bean gum, and xanthan gum bound to the intact cells, and that schizophyllan, xanthan gum, and succinoglycan bound to the protoplasts. These adhesive beta-d-glycans raised considerably the number of the cells regenerated from protoplasts. The results suggest that some water soluble beta-d-glycans showing affinity for intact cells and/or protoplasts will be suitable for use as stabilizers of protoplast division.     

一种水包油包胶型乳液的制备及其在乳化肠中的应用

以结冷胶和无水氯化钙为内水相凝固剂,酪蛋白酸钠为外水相乳化剂,制备一种水包油包胶（S/O/W）型 乳液。以多重乳液粒径和分布为指标,研究酪蛋白酸钠添加量对S/O/W型多重乳液加工适应性的影响。结果表明： 正交试验得到S/O型单重乳液最佳制备条件为：内水相中结冷胶添加量0.2%、无水氯化钙添加量0.5%;内水相乳化 剂聚甘油蓖麻醇酯添加量2.5%;油相为精炼猪油,油水体积比3∶2;剪切速率17 500 r/min,剪切时间1.5 min。将制 得的S/O型单重乳液与不同添加量酪蛋白酸钠混合制得S/O/W型多重乳液。当酪蛋白酸钠添加量0.1%时,S/O/W型 多重乳液粒径符合加工要求,且贮藏、热处理、剪切稳定性较好。以多重乳液替代猪脂肪制备的低脂乳化肠与高脂 （精炼猪油含量20%）乳化肠外观不存在明显差异;微观结构观察结果表明,多重乳液在乳化肠中包裹良好、分布 均匀。     

亲水性胶体对广式腊肠水分迁移及质构的影响

本文研究了卡拉胶、魔芋胶、瓜尔豆胶及其复配对广式腊肠烘烤过程中水分迁移、产品质构、感官等质量品质的影响。结果表明,广式腊肠添加亲水性胶体后,可略有提高产品的水分含量,尤其是瓜尔豆胶组(19.94%),比对照提高4.02%;在烘烤中期,亲水性胶体可降低广式腊肠的干燥速率,整体而言,亲水性胶体对烘烤过程中水分散失影响较小。胶体添加组感官得分除D3组,均高于对照组,其中添加复配卡拉胶与魔芋胶的感官综合得分最高,达到87.5;除瓜尔豆胶外,单独胶体和复配胶均能一定程度上改善广式腊肠的质构特性,尤其是复配胶体组。广式腊肠添加亲水性胶体后,复水率显著提高(p0.05),尤其是瓜尔豆胶及其复配组,达到3.79%。复配胶的加入可改善广式腊肠的感官品质、质构特性及复水性,不同亲水性胶体有不同的作用特点。     

Rheology and modelling of aqueous gum solutions commonly used in the food industry

Rheological properties of solutions prepared using xanthan (XG), locust bean (LBG) or sodium carboxymethyl cellulose (CMC) gums, and their binary mixtures were studied. The influence of shear rate, total gum content, measurement time and temperature on the apparent viscosity was investigated. In the binary mixtures, the presence of different gum ratios at several total gum content was also analysed. XG solutions were always the most stable, providing high viscosity values which rose notably with increasing gum content. XG/LBG and CMC/XG mixtures depicted high values of viscosity for very low gum amounts. Viscosity did not change with measurement time in mixtures containing XG, whereas varied with measurement temperature. This variation was lower for samples with larger total gum content. The viscosity was also modified when different gum ratios were tested. A mathematical model was proposed to evaluate the combined effect of temperature, concentration and shear rate on the apparent viscosity.     

Reactivity of Modified Starches with Isocyanates

Various substituents were added onto starch by means of esterification or etherification so that their effect on reactivity of starch with isocyanates in a nonpolar solvent could be studied. Maximum reactivity of the modified starches was achieved when the degree of substitution (D.S.) was about 0.7. Cured urethane plastics made from formulations containing 20 % of the starch derivatives demonstrated maximum breaking energy at D.S. 0.7.     

Identification of two additives, locust bean gum (E-410) and guar gum (E-412), in food products by DNA-based methods.

Locust bean gum (E-410) and guar gum (E-412) are high molecular weight galactomannans used by the food industry as versatile food additives. The compounds, although chemically closely related, do not have the same functional properties when used in foods, and the substitution or unadvertised addition of either could change the desired qualities of the product. Analytical discrimination between E-410 and E-412 is technically difficult since they only differ in their galactose: mannose ratios, being 1 : 4 and 1 : 2 for locust bean gum and guar gum, respectively. A qualitative DNA-based method is reported for the authentication of additives E-410 and E-412 in finished food products (ice cream, dehydrated desserts, milk derivatives, dehydrated soups, salad dressing, marmalade and meat) from small quantities of food. DNA sequences from the nuclear ribosomal spacers of Ceratonia siliqua and Cyamopsis tetragonoloba, the plant sources of E-410 and E-412, respectively, were used to design polymerase chain reaction primers specific for each additive (PA23/PA21 and PG22/PG21). Twenty-two foods were analysed for the presence of E-410 and E-412 additives by this single-step polymerase chain reaction-based method. Positive DNA amplifications with the E-410 and/or E-412 primers were obtained in all 19 samples reported to contain either additive.     

明胶与阿拉伯胶复合凝聚法制备脂肪替代品的研究

随着人们对高油脂食品对健康影响的认识,脂肪替代品开发的意义越来越大。本实验以明胶和阿拉伯胶为主要原料通过复合凝聚法制备脂肪替代品(FS),得到FS产率高达4.93的生产工艺：pH4.25,明胶溶液与阿拉伯胶溶液配比1:1、搅拌温度50℃、静置时间为0.5h、溶质浓度2%、搅拌速度100r/min。产品的外观类似油脂,体积平均粒径在10μm左右,满足脂肪替代品特性要求。