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     

Determination of Pectin in the Presence of Food Polysaccharides

A selective and specific method to assay pectin in mixtures of polysaccharides using pectinase was developed. The mixture was extracted with 99.5% (v/v) ethanol to remove gum arabic and any other ethanol-soluble saccharides and polysaccharides; pectin was then hydrolyzed with pectinase. The hydrolyzed pectin was recovered by solution in 80% (v/v) ethanol and assayed by the m-hydroxybiphenyl method. The assay was not affected by agar and gums of tragacanth, karaya, guar, and locust bean in the mixture. Alginate and xanthan gum in the mixture repressed the development of color by this method, but this effect could be offset by modification of the pectinase reaction system.     

Study of emulsions stabilized with Phaseolus vulgaris or Phaseolus coccineus with the addition of Arabic gum, locust bean gum and xanthan gum

The properties of o/w emulsions stabilized with 1%w/v common bean (Phaseolus vulgaris L.), V or scarlet runner bean (P. coccineus L.), Coc extracted by isoelectric precipitation or ultrafiltration, at pH 7.0 and 5.5, with the addition of Arabic gum, locust bean gum, xanthan gum and a mixture of xanthan gum–locust bean gum (0.1 %w/v and 0.25 %w/v) are studied. The stability of emulsions was evaluated on the basis of oil droplet size, creaming, viscosity and protein adsorption measurements. The addition of Arabic gum, caused an increase in D[4,3] values and a decrease in the amount of protein adsorbed at the interface. The addition of locust bean gum in some emulsions reduced the amount of protein adsorbed. The addition of xanthan and to a less extend of the polysaccharide mixture, promoted a decrease in D[4,3]. So, emulsion stability was affected by the polysaccharide nature. Differences were also observed with respect to the protein nature, the method of its preparation and emulsion's pH. All polysaccharides enhanced the emulsions viscosity with xanthan and xanthan–locust bean gum exhibiting the higher values. V isolates and isoelectricaly precipitated isolates of both V, Coc showed higher viscosity values. The stability was enhanced by the increase of the viscosity of the continuous phase and the creation of a network, which prevents the oil droplets from coalescence.     

PHYSICAL,CHEMICAL AND SENSORY PROPERTIES OF SUGAR‐FREE JELLY*

The increase in diabetes and obesity has increased the demand for sugar‐free/low‐calorie products. Three jelly formulations were prepared using sucralose, low‐methoxyl pectin and maltodextrin with either xanthan gum or locust bean gum (LBG) used singly or in combination and stored at 4C or 43C for shelf life evaluation. Jelly treatments were evaluated for chemical, physical and sensory properties. The combination of xanthan gum and LBG significantly reduced syneresis compared with either gum used singly. The combination of xanthan gum and LBG resulted in significantly higher firmness and springiness values than using xanthan gum or LBG alone. The overall acceptability, aroma, taste, texture, spreadability and sensory attributes for no sugar‐added grape jelly averaged 5.8–6.4 in a 9‐point hedonic scale consumer acceptance study.     

Surface tension of Phaseolus vulgaris and coccineus proteins and effect of polysaccharides on their foaming properties

The surface tension of protein isolates from common bean (Phaseolus vulgaris L.) and scarlet runner bean (Phaseolus coccineus L.), prepared by isoelectric precipitation and ultrafiltration was evaluated, with respect to protein concentration (0.001–0.1% w/v) and pH (pH 4.5, 5.5, 7.0 and 8.0). Surface tension was most reduced, and with a higher rate of reduction at higher protein concentration and at pH 8.0. Foams (1, 2% w/v protein), at the same pH values, with and without the addition of polysaccharides, were studied. The proteins’ foaming behaviour was related to their adsorption behaviour. Arabic gum, locust bean gum (0.1% and 0.25% w/v), xanthan gum and a xanthan/locust bean gum mixture (0.1% w/v) had a positive effect on foam creation. All polysaccharides increased foam stability, probably due to the viscosity increase and to the creation of a network, which prevents the air droplets from coalescence. Isolates from P. coccineus and isolates obtained by ultrafiltration seemed to exhibit better foaming properties.     

MODEL PREDICTION FOR SENSORY ATTRIBUTES OF NONGLUTEN PASTA

Response surface methodology was used to predict sensory attributes of a nongluten pasta and develop response surface plots to help visualize the optimum region. Optimum regions of xanthan gum, modified starch, and locust bean gum were selected by overlapping the contour plots of sensory properties of nongluten pasta as compared with the control pasta. The formula of nongluten pasta that possessed the most desirable properties was xanthan gum at 40 g, modified starch at 35 g, locust bean gum at 40 g, tapioca starch at 113 g, potato starch at 57 g, corn flour at 250 g, and rice flour at 50 g. The quality of nongluten pasta could be improved by using different levels of nongluten starches and flours, and nonstarch polysaccharides.     

增稠剂和乳化剂对豆浆稳定性的影响

为增加豆浆的稳定性,采用测定豆浆稳定系数、表面张力及进行感官评分的方法筛选适合用于豆浆样品的增稠剂和乳化剂,确定了最适宜的豆浆增稠剂和乳化剂的种类及其用量。经过黄原胶、刺槐豆胶、卡拉胶、结冷胶和海藻酸钠的单因素实验,黄原胶和刺槐豆胶的复配实验及黄原胶、刺槐豆胶和乳化剂(单硬脂酸甘油酯和蔗糖脂肪酸酯)的正交实验得出以下结果:黄原胶和刺槐豆胶对增加豆浆稳定性有着较好的效果,当它们的质量浓度分别为0.2g/L时,其稳定系数分别为0.737、0.742。单硬脂酸甘油酯和蔗糖脂肪酸酯复配后HLB=8、质量浓度为2g/L时,豆浆样品的稳定性最好,表面张力为41.7mN/m。当黄原胶、刺槐豆胶、乳化剂质量浓度(单硬脂酸甘油酯质量∶蔗糖脂肪酸酯质量=7∶4)分别为0.14、0.14、2g/L时豆浆的稳定性最好,此时豆浆样品的稳定系数为0.879,表面张力为41.6mN/m,感官评分为96。     

刺槐豆胶与黄原胶复配体系的流变性

研究刺槐豆胶/黄原胶复配体系的流变性,并采用流变学的Cross模型进行拟合分析。结果表明:刺槐豆胶与黄原胶复配可以产生协同作用,当刺槐豆胶与黄原胶的复配体积比为4∶6时,复配体系的黏度最大,触变测试中形成的滞后环面积最大,并且在黏弹性测试中储能模量G’表现出最大值。因此,刺槐豆胶与黄原胶的最佳复配比例为体积比4∶6。对最佳比例复配体系进行不同温度处理后测试可知,最佳复配体系的最适处理温度为80℃,得到的复配体系黏度最大;复配体系的p H值在6.0~10.0之间时,其黏度变化较小,保持相对稳定。     

Effects of nonprotein substances on protein hydrolysis and plastein formation

Effects of various naturally occurring nonprotein substances (carbohydrates, polysaccharides, fats and salts) on enzymatic hydrolysis of soy protein isolate and plastein formation from hydrolyzed soy protein were investigated. Relative extent of hydrolysis and plastein formation were measured as protein solubility in 10% trichloroacetic acid (TCA) since this method was found suitable for analysis of turbid, viscous and/or low protein samples. The presence of guar, xanthan, locust bean and arabic gums, arabinogalactan, unsaturated fatty acids (2%), salt mixture and xylan were found to enhance soy protein peptic hydrolysis at 0·5% enzyme/substrate; unsaturated fatty acids (1%) inhibited hydrolysis. At enzyme/substrate of 3·5%, hydrolysis was enhanced by xanthan gum, unsaturated fatty acids and sodium chloride but inhibited by gum karaya, salt mixture, starch, cellulose, and saturated fatty acids. Plastein synthesis was inhibited by xanthan, locust bean and guar gums but stimulated by arabinogalactan. Several nonprotein substances were found to interfere with the TCA solubility assay. Positive interference was noted for systems containing saturated and unsaturated fatty acids and magnesium, but negative interference was observed for systems containing guar gum, xanthan gum, calcium chloride and gum arabic.     

Effect of gums on the multi-scale characteristics and 3D printing performance of potato starch gel

This research investigated the multi-scale characteristics of potato starch gel (PSG) with different addition ratios of xanthan gum (XG) and locust bean gum (LBG). These characteristics are closely related and had significant impacts on 3D printing performance. Both xanthan gum and locust bean gum were able to increase the apparent viscosity, storage modulus (G′) and loss modulus (G″) of the blended gel system to varying degrees. Large amplitude oscillation shear (LAOS) was used to detect slight rheological differences led by microstructure changes. The critical strain values of the blended gel system rose as the addition ratio of locust bean gum increased. At the same time, the elastic and viscous Lissajous curves could characterize the viscoelastic changes under large strains. Fourier transforms infrared spectroscopy (FT-IR) illustrated that locust bean gum could strengthen the hydrogen bonds so that the gel had stronger mechanical properties compared with the addition of xanthan gum. Scanning electron microscopy (SEM) could observe the changes in the microstructure of the blended gel systems with addition of different addition ratios of gums. From the perspectives of 3D printing results and data analysis, the appropriate amount of xanthan gum improved the fineness and fluidity of the gels by virtue of its lubricating and coating characteristics, while the locust bean gum enabled them to have stronger shape retention abilities and better performances of resisting compressed deformation.     

Effects of soy protein hydrolysis and polysaccharides addition on foaming properties studied by cluster analysis

The objective of the work was to study foaming properties (foam overrun, drainage rate and collapse stability) of soy protein and their hydrolysates as affected by polysaccharides. As starting material a sample of commercial soy protein isolate was used (SP) and hydrolysates of 0.4, 5.0 and 5.2% degree of hydrolysis (DH) were produced by an enzymatic reaction. The polysaccharides added were xanthan, λ and κ-carrageenan, guar, locust bean gum and hydroxypropylmethylcelluloses as surface-active polysaccharides.     

Swallowing profiles of food polysaccharide solutions with different flow behaviors

The relationship between physiological response and sensory perceived scores in swallowing was investigated using food polysaccharide solutions. Solutions from xanthan gum (0.3–0.9%) and locust bean gum (0.5–0.8%) were used as specimen with different flow behaviors identified by static and dynamic rheological methods. Acoustic analysis and sensory evaluation were carried out to investigate the swallowing profiles using the same human subjects. From acoustic analysis, time required for bolus to transfer through the pharyngeal phase t₂ decreased with increasing concentration of xanthan gum despite the viscosity increase. Also, the acoustic balance for the swallowing sound shifted to a higher frequency range with increasing concentration. The t₂ for locust bean gum was much less concentration-dependent and consistently larger than that for xanthan gum when compared at equivalent shear viscosity at 10 s⁻¹. Also, the acoustic balance for the swallowing sound was less concentration-dependent than that for xanthan gum. From sensory evaluation, 0.6% xanthan gum was scored the highest in perceived swallowing ease, while 0.75% locust bean gum was scored the lowest. Both t₂ and the acoustic balance correlated well with perceived swallowing ease. Results indicate that xanthan gum solutions flow as one coherent bolus through the pharyngeal phase with smaller variation of flow velocity than locust bean gum solutions, leading to a greater sensation of swallowing ease. “Structured fluid”, defined as fluid with yield stress such as xanthan gum solutions, is a rheological nature that allows bolus to be swallowed in one go, relating to perceived swallowing ease of liquid foods.     

Rheological behaviour of pullulanase-treated guar galactomannan on co-gelation with xanthan

The present study involves the use of non-specific enzyme pullulanase (from Bacillus acidopullulyticus) to remove galactose residues from guar galactomannan to obtain modified guar galactomannan mimicking the functional properties of locust bean gum. The modified guar galactomannan blended with xanthan exhibited the rheological behaviour of elastic modulus (G′) greater than viscous modulus (G″) with a decrease in tan δ value similar to locust bean gum/xanthan blend. Also a twofold increase in the magnitude of elasticity compared to xanthan alone suggested the synergistic interaction with formation of three dimensional networks. The modified guar galactomannan with galactose content of 21% and M:G ratio 1:3.8, almost akin to locust bean gum, showed a better interaction with xanthan. Dynamic stress sweep study of modified guar galactomannan/xanthan blend with increased yield stress of 800 dynes/cm² also indicated the synergistic behaviour. Modified guar galactomannan also revealed the maximum synergistic interaction with xanthan at a mixing temperature of 60 °C than at 20 °C, 30 °C, 40 °C and 50 °C, respectively. Modification of guar galactomannan by pullulanase is an alternative route to produce galactose-depleted guar galactomannan with enhanced rheological functionalities on co-gelation with xanthan, as a cost effective replacement to locust bean gum.     

Effect of locust bean/xanthan gum addition and replacement of pork fat with olive oil on the quality characteristics of low-fat frankfurters

The effects of reducing fat level from 20% to 12% and 9%, substituting pork fat with olive oil and adding locust bean/xanthan gum (0.5% and 0.6%) on emulsion stability, jelly and fat separation, processing yield, cook loss, texture and sensory characteristics of frankfurters were investigated and compared with control samples. Addition of locust bean/xanthan gum produced a significant increase in hydration/binding properties, characterised by lower cook losses, increasing yield, better emulsion stability and lower jelly and fat separation. The substitution of pork fat by olive oil did not affect these parameters. Indeed, results showed that reducing fat levels together with increasing moisture and locust bean/xanthan gum addition do not affect the sensory or textural properties, but olive oil addition produces a decrease in hardness and an increase in adhesiveness, however the overall acceptability was not affected.     

Interactions of κ-carrageenan Plus Other Hydrocolloids in Fish Myosystem Gels

ABSTRACT: Mixtures of κ-carrageenan plus other hydrocolloids (locust bean, guar, xanthan, iota-carrageenan, sodium carboxymethylcellulose, and sodium alginate) were examined for their effects on the mechanical and water holding properties of heat-induced gels made from washed blue whiting mince. Gel structure and thermal behavior were also studied. No synergistic effect was detectable through functional properties except for the mixture of κ-carrageenan with locust bean gum. Light microscopy revealed that κ-carrageenan and xanthan mixed locally with locust bean at its rich domains. κ-carrageenan and xanthan presented interactions with the protein matrix, which were more discernible in the first case. Differential scanning calorimetry (DSC) revealed faint interactions for the mixtures of κ-carrageenan with locust bean and with xanthan, and weakly synergistic gelling effects between the last two hydrocolloids. The blend of κ-carrageenan with sodium alginate exhibited thermally strong synergistic interactions but no particular effects were induced on corresponding functional properties.     

Synergistic interaction of xanthan gum with glucomannans and galactomannans

Xanthan gum forms thermoreversible gels when mixed with konjac mannan or locust bean gum. The stronger gels are formed with konjac mannan and the maximum gel strength for the mixed systems in the absence of electrolyte occurs at a xanthan-konjac mannan or xanthan-locust bean gum mixing ratio of about 1:1. In the presence of 0.04 mol/dm³ NaCl the optimum mixing ratio is unchanged for xanthan-locust bean gum blends but changes to about 2:1 for xanthan-konjac mannan blends. These observations support differential scanning calorimetric data which are able to monitor both gelation and the conformational transition of the xanthan molecules and indicates that (i) in the absence of electrolyte konjac mannan interacts with disordered xanthan chains whilst in the presence of 0.04 mol/dm³ NaCl it interacts with ordered xanthan chains, and (ii) locust bean gum interacts with ordered xanthan chains both in the presence and absence of electrolyte.     

Enhanced Sweetness in Sweetener-NaCI-Gum Systems

Enhancement of sweetness in aqueous gum (0.03%, w/v) sweetener systems by added NaCl (0.05%, w/v) was evaluated by a sensory panel. ²³Na NMR spectroscopy was used to determine Na⁺ binding and its relationship to sweetness elicited by glucose, lactose, maltose, sucrose and aspartame. Sweetness intensity differed due to gum (p = 0.0001) and sweetener (p = 0.0001), but was not affected by NaCl (p = 0.0774). Sweetness increased with added NaCl in xanthan, guar and locust bean gum solutions. However, sweetness decreased in k-carrageenan systems possibly due to endogenous cation (Ca²⁺, K⁺ and Na⁺) content, which influences Na⁺ mobility. The sweetest systems containing lactose and/ or xanthan, showed the greatest enhancement by NaCl.     

Effects of gelatinisation level, gum and transglutaminase on the quality characteristics of rice noodle

The aim of the present study was to investigate the effects of gelatinisation level, gum (locust bean gum, xanthan gum, 3%) and/or transglutaminase (TG, 0.5%) on quality characteristics of rice noodle. In order to improve the dough forming ability, rice flour was gelatinised at levels of 15%, 20%, 25% and 30%. Noodle samples were evaluated in terms of cooking loss, total organic matter (TOM), water absorption, swelling volume, maximum force, colour, sensory properties, pasting properties. Noodle sample with a gelatinisation level of 25% had better cooking and sensory properties. Gum and/or TG were added to this noodle formula. The noodle samples including xanthan gum had better cooking and sensory properties. TG caused a significant decrease in TOM. The samples including locust bean gum had significantly higher maximum force values. Xanthan gum caused decreases in some Rapid ViscoAnalyzer viscosity values of the noodle samples, while locust bean gum caused increases.     

Effects of xanthan and galactomannan on the freeze/thaw properties of starch gels

Three starches (maize, rice and wheat), and the two non-starch polysaccharides xanthan and locust bean gum galactomannan (LBG) were examined in gel and dough systems for texture and stability properties during freezing and low temperature storage. Xanthan and LBG were found to confer increased resistance to freeze/thaw cycling on rice starch gels but the non-starch polysaccharides had little effect on the performance of maize and wheat starch gels or on wheat dough.     

TEXTURE STABILITY OF HYDROGEL COMPLEX CONTAINING CURDLAN GUM OVER MULTIPLE FREEZE–THAW CYCLES

The texture stability of hydrogel complexes containing curdlan gum over multiple freeze–thaw cycles (FTCs) was investigated. The hydrogels formed by curdlan and xanthan gum, locust bean gum, carrageenan or guar gum at various combinations were stored at 4C for 24 h before subjected to five FTCs alternating between − 16 (18 h) and 25C (6 h). Xanthan/curdlan hydrogels showed the highest freeze–thaw stability in terms of syneresis, heat stability and adhesiveness. The viscosity of xanthan/curdlan combination was the lowest among all samples studied yet the most stable over the five FTCs, whereas significant changes were observed with locust bean/curdlan hydrogels. The guar/curdlan combination before freeze–thaw treatments exhibited predominant elasticity; however, as the cycles progressed the elasticity decreased. The most stable gel strength was achieved when curdlan was combined with guar or xanthan at 2% (w/v) total concentration, while carrageenan/curdlan gels were the least stable.

PRACTICAL APPLICATIONS

Texture instability remains the most significant challenge for frozen food products, especially with inevitable post-production temperature fluctuations. Loss of moisture and changes in textural attributes often results in significant reduction of product quality. Precise control of hydrogel complexes that provide texture stabilization over multiple freeze–thaw cycles will enhance the quality of existing products while enabling the development of new ones.