Effect of Drying Conditions on Rheological Properties of Hydrocolloids Gums from <i>Triumfetta cordifolia</i>and <i>Bridelia thermifolia</i>Barks

Triumfetta cordifolia and Bridelia thermifolia are two shrubs from tropical region of Africa. Their gums are traditionally extracted from fresh barks and used in traditional recipes (thickening and aromatization of sauces, improvement of the swelling of maize and bean cakes) and in the process of decantation of traditional beer. In order to valorize these barks in dried form, study of the effect of drying temperature on the rheological properties of their gums was carried out. In this respect, the fresh barks were dried at 40℃, 50℃, 60℃, 70℃ and 80℃ and the viscosity of their extracts was measured. The drying kinetic of the barks showed two falling rate periods represented by two drying constants?k1 and k2. The absolute viscosity of the extracts decreased beyond drying temperatures higher than 70℃ and 80℃respectively for T cordifolia and B. Thermifolia. The decreasing viscosity is attributed mainly to a reorganization of polysaccharide chains. The temperatures range lower than 70℃ could be retained to dry the barks and to extract gums without deteriorating their properties.

Simulation of Flamboyant Gums (Power Fluid) with the Lattice Boltzmann Method

From results obtained in the rheological characterization of a 4% dispersion of flamboyant gum with the HaakeRT20 viscometer, for different conditions of pH = 3.0 and 9.0, temperature 5°C, 25°C and 45°C, the data of the rheological behavior of the gum dispersions were fitted to the power law model. To understand and predict the behavior of this gum, a model of Lattice Boltzmann D2Q9 was developed for the behavior, in addition to simulations for the conditions handled in the experiments performed with the HaakeRT20 viscometer.

Rheological Properties of Six Plant-Based Seed Gums

The rheological properties of six mucilage solutions (Guar Gum, Locust Bean Gum, Tamarind Gum, Flaxseed Gum, Artemisia Sphaerocephala Krasch Gum and Cassia Gum) have been examined. It was found that all six gums could be classified into three different types according to the changes of viscosity with increasing shear rate. Steady shear viscous properties in a range of shear rate from 0.1 to 100 s-1 were investigated in the provision of mucilage concentration, pH, temperature and salts. A non-Newtonian shear-thinning behavior was observed. The data of viscosity-shear successfully correlated Power law model. Apparent viscosity was apparently dependent on mucilage concentration increasing significantly as mass fraction went up. A marked dependence of viscosity on temperature was also observed;as temperature increased, the viscosity decreased sharply. The value n of flaxseed gum is minimum, which means it behaves the greatest shear-thinning properties. Both Guar gum and Tamarind gum possessed better acid-proof and alkali-proof advantages. The flow activation energy of ASKG is 4.3 kcal which is higher than other gums so that the influence of temperature on characteristics of viscosity is stronger. The mechanical spectra in the linear viscoelasticity region were studied in the temperature range from 20&deg;C to 90&deg;C, at a frequency range from 0.1 to 10 Hz. It was observed that Both elastic modulus G' and viscous modulus G" behaviors were found to be dependent on temperature and frequency. What have been investigated in this work could provide guidance for practical application in the field of food industry.

Rheological Properties of Five Plant Gums

The rheological properties of five gum solutions (Gum Shiraz, Karaya Gum, Ghatti Gum, Arabic Gum and Gum Tragacanth) have been examined. The five mucilage solutions exhibited non-Newtonian, shear-thinning with thixotropy at higher concentrations (0.5% - 1%, m/v). According to the change of viscosity with increasing temperature, all five gums could be defined as three types: gum tragacanth and gum shiraz have a good temperature stability;karaya gum is affected by temperature obviously;the remaining two gums have a general stability. The viscosity of mucilage solutions (Arabic Gum, Ghatti Gum and Karaya Gum) had an apparent dependence on temperature. The parameter n of Shiraz Gum is the minimum, which means it has the best flow properties. The flow activation energy of karaya gum is 2.683 kcal which is the highest than other gums so that it has a great influence on temperature. The gum solutions’ viscosity had different sensitive degree over tested pH range (pH 2 - 10). Shiraz gum and arabic gum possessed better acid-proof and alkali-proof respectively. The addition of salts (NaCl and CaCl2) led to the reduction of viscosity, which was more sensitive to Ca2+ than to Na+. Both storage modulus G’ and loss modulus G” of all five gums had a dependence on temperature and frequency. These results are potentially useful for the application in the field of food processing.

Fractional Order for Food Gums: Modeling and Simulation

Fractional order calculus can represent systems with high-order dynamics and complex nonlinear phenomena using few coefficients, since the arbitrary order of the derivatives provides an additional degree of freedom to fit a specific behavior. Numerous mathematicians have contributed to the history of fractional calculus by attempting to solve a fundamental problem to the best of their understanding. Each researcher sought a definition and therefore different approaches, which has led to various definitions of differentiation and anti-differentiation of non-integer orders that are proven equivalent. Although all these definitions may be equivalent, from one specific standpoint, i.e., for a specific application, some definitions seem more attractive. Furthermore, it is well known that food gums are complex carbohydrates that can suit for a wide variety of functions in the context of food engineering. The viscoelastic behavior of food gums is crucial for these applications and formulations of new or improved food products. Small progress has been made to understand the viscoelastic behavior of food gums and there are few studies in the literature about these models. In this paper, we applied the Riemann-Liouville approach and the Fourier transform in order to obtain numerical simulations results of a fractional derivative model based on previous literature that to make a quantitative description of the viscoelastic properties behavior for a food gum. The results reveal that the fractional model shows good simulation capability and can be an attractive means for predicting and to elucidate the dynamic viscoelastic behavior of food gums.

Use of seed gums from Tamarindus indica and Cassia fistula as controlled-release agents

Most seed gums have been widely used in oral and topical pharmaceutical formulations, cosmetics, and food products because of their hydrophilic properties. Gums from Tamariudus indica and Cassia fistula seeds were chemically modified by carboxymethylation to improve their functionalities. The objective of the present study was to characterize and evaluate crude and carboxymethylated gums from T. indica and C. fistula seeds to achieve the controlled-release of diclofenac sodium(DS) in matrix tablet form. Both crude and carboxymethylated gums were characterized by Fourier transform infrared spectroscopy, Xray diffraction, and scanning electron microscopy. The results revealed that the gums were successfully modified by carboxymethylation and that the modified gums were amorphous in structure and had better flow properties. The carboxymethylated gums from both plant seeds did not exhibit cytotoxicity at concentrations lower than 0.5 mg/ml. All gum samples used as polymeric controlled-release agents were formulated into DS matrix tablets. Hardness and thickness tests were conducted as in-process tests. Drug content estimation and in vitro drug release studies were carried out to evaluate the matrix tablets. Increasing the concentration of gums increased compression time and hardness while it reduced the thickness. Furthermore, the results fitted well with the Korsmeyer–Peppas model. Moreover, the DS tablets were found to release the drug by super case II transport(relaxation). In summary, the carboxymethylated gum from T. indica and C. fistula seeds is an excellent, naturally sourced gum with high physicochemical and functional qualities, and can potentially be used in pharmaceutical applications as a disintegrant, diluent, and drug release-controlling agent.

Experimental investigation into effects of the natural polymer and nanoclay particles on the EOR performance of chemical flooding in carbonate reservoirs

This paper aims to investigate the tragacanth gum potential as a natural polymer combined with natural clay mineral(montmorillonite,kaolinite,and illite)nanoparticles(NPs)to form NP-polymer suspension for enhanced oil recovery(EOR)in carbonate reservoirs.Thermal gravimetric analysis(TGA)tests were conducted initially in order to evaluate the properties of tragacanth gum.Subsequently,scanning electron microscopy(SEM)and energy-dispersive X-ray(EDX)tests were used to detect the structure of clay particles.In various scenarios,the effects of natural NPs and polymer on the wettability alteration,interfacial tension(IFT)reduction,viscosity improvement,and oil recovery were investigated through contact angle system,ring method,Anton Paar viscometer,and core flooding tests,respectively.The entire experiment was conducted at 25,50,and 75℃,respectively.According to the experimental results,the clay minerals alone did not have a significant effect on viscosity,but the addition of minerals to the polymer solution leads to the viscosity enhancement remarkably,resulting mobility ratio improvement.Among clay NPs,the combination of natural polymer and kaolinite results in increased viscosity at all temperatures.Considerable wettability alteration was also observed in the case of natural polymer and illite NPs.Illite in combination with natural polymer showed an ability in reducing IFT.Finally,the results of displacement experiments revealed that the combination of natural polymer and kaolinite could be the best option for EOR due to its substantial ability to improve the recovery factor.

Alleviation of the plastic deformation of gel ink under strong stress through an esterification of xanthan gum reinforcing its double helix structure

As a natural organic polymer,xanthan gum(XG)can alleviate the plastic deformation of gel ink under strong stress and realize the reasonable regulation of the rheological properties of gel ink.However,as the double-helix structure connected by hydrogen bonds cannot resist the mechanical environment of strong stress,XG shows poor shear resistance.In this study,a polymer gel with interpenetrating polymer network structure was prepared by esterifying XG,taking polystyrene maleic anhydride(SMA)as the modifier.In addition to retaining the excellent rheological properties of XG,the generated polymer gel also exhibited high shear resistance.The optimal addition amount of the esterification reaction modifier was determined as mXG:mSMA=5:3 according to the gel ink standard.With this amount,the viscosity of the modified xanthan gum(SXG)gel increased to 1578.8 mPa·s and 100.7 mPa·s at shear rates of 4 s1 and 383 s1,respectively,and the shear resistance increased more than 2 times compared to the unmodified one.It is because of the ester bond formed by esterification that the reaction strengthens the interaction between molecular segments,enabling the new gel to resist to strong mechanical stress.The new polymer gel studied in this paper and the proposed mechanism of action provide new insights for the development of high-end gel ink and also provide theoretical support for the study of rheological properties of non-Newtonian fluids.

基于GUM法的风电叶片结构试验方法不确定度研究

针对风电叶片全尺寸结构试验方法,首先分析试验过程中所需测量物理量的不确定度因素来源;其次利用GUM法建立不确定度数学模型,然后评定各部分输入量的标准不确定度;最后分析得到叶片结构试验各测试物理量的合成标准不确定度和扩展不确定度,从而建立风电叶片试验不确定度的系统评价方法。

自适应MCM法和GUM法评价直接进样测汞法测定稻谷中总汞的不确定度比较研究

重金属汞污染是危害粮食安全的重要问题,直接进样测汞法的检测过程中需要对检测结果做好质量控制。检测结果需要识别实验过程中各环节对结果的影响大小。基于GB/T 27404—2008《实验室质量控制规范食品理化检测》附录F中对实验室开展新项目所需验证的各种项目:回收率、标准曲线、测定低限、精密度、准确度等。使用自适应蒙特卡洛法(adaptive Monte Carlo method,MCM)和测量不确定度表示指南方法(Guide to the expression of uncertainty in measurement,GUM)分别对直接进样测汞法开展不确定度评定。GUM法得到的不确定范围为(0.0193±0.0017)mg/kg(k=2);MCM法得到的不确定度置信区间(95%)为[0.0177,0.0211];使用MCM Alchimia软件对2种方法的不确定度概率密度拟合曲线,MCM法与GUM法评价结果一致性较好。分析不确定度评定过程中各不确定度贡献率,回收率和标准曲线拟合过程引入不确定度在检出限处引入的不确定度分量较大,建议在方法验证和不确定度评定中使用定量限作为加标回收率和标准曲线最小浓度点。

A Novel Fracturing Fluid with High-Temperature Resistance for Ultra-Deep Reservoirs

Ultra-deep reservoirs play an important role at present in fossil energy exploitation.Due to the related high temperature,high pressure,and high formation fracture pressure,however,methods for oil well stimulation do not produce satisfactory results when conventional fracturing fluids with a low pumping rate are used.In response to the above problem,a fracturing fluid with a density of 1.2~1.4 g/cm^(3)was developed by using Potassium formatted,hydroxypropyl guanidine gum and zirconium crosslinking agents.The fracturing fluid was tested and its ability to maintain a viscosity of 100 mPa.s over more than 60 min was verified under a shear rate of 1701/s and at a temperature of 175℃.This fluid has good sand-carrying performances,a low viscosity after breaking the rubber,and the residue content is less than 200 mg/L.Compared with ordinary reconstruction fluid,it can increase the density by 30%~40%and reduce the wellhead pressure of 8000 m level reconstruction wells.Moreover,the new fracturing fluid can significantly mitigate safety risks.

Effect of defatted flaxseed gum powder addition on the quality of sesame paste

The study explored the influence of defatted flaxseed gum powder(DFGP) on the stability and quality of sesame paste by measuring and analyzing its composition, color, texture, particle size, centrifugal oil separation rate,rheological properties, and microstructure. The results showed that the moisture and polysaccharide content of sesame paste was increased as the DFGP increased. Additionally, the hardness, gumminess, and chewiness of the sesame paste was improved, while the presence of particles with small particle size(1–100 μm) was decreased.The rate of oil precipitation was reduced by 28.99% when the amount of DFGP was 6%. The sesame paste samples exhibited pseudoplastic behavior, demonstrating shear thinning. As the shear rate increased, the apparent viscosity of sesame paste gradually decreased. Both the storage modulus(G’) and the loss modulus(G’’) increased as the shear frequency increased. The microstructure observation revealed that protein and oil were evenly distributed in the sesame paste system, and the addition of DFGP enhanced the bonding between oil and protein.This study can provide valuable references for high-quality sesame paste products in the food industry.

Enhancement of the Antigenotoxic and Antioxidant Actions of Eugenol from Spice Clove and the Stabilizer Gum Arabic on Colorectal Carcinogenesis

Spices are defined as any aromatic condiment of plant origin used to alter the flavor and aroma of foods. Besides flavor and aroma, many spices have antioxidant activity, mainly related to the presence in cloves of phenolic compounds, such as flavonoids, terpenoids and eugenol. In turn, the most common uses of gum arabic are in the form of powder for addition to soft drink syrups, cuisine and baked goods, specifically to stabilize the texture of products, increase the viscosity of liquids and promote the leavening of baked products (e.g., cakes). Both eugenol, extracted from cloves, and gum arabic, extracted from the hardened sap of two species of the Acacia tree, are dietary constituents routinely consumed virtually throughout the world. Both of them are also widely used medicinally to inhibit oxidative stress and genotoxicity. The prevention arm of the study included groups: Ia, IIa, IIIa, Iva, V, VI, VII, VIII. Once a week for 20 weeks, the controls received saline s.c. while the experimental groups received DMH at 20 mg/kg s.c. During the same period and for an additional 9 weeks, the animals received either water, 10% GA, EUG, or 10% GA + EUG by gavage. The treatment arm of the study included groups Ib, IIb, IIIb e IVb, IX, X, XI, XII). Once a week for 20 weeks, the controls received saline s.c. while the experimental groups received DMH at 20 mg/kg s.c. During the subsequent 9 weeks, the animals received either water, 10% GA, EUG or 10% GA + EUG by gavage. The novelty of this study is the investigation of their use alone and together for the prevention and treatment of experimental colorectal carcinogenesis induced by dimethylhydrazine. Our results show that the combined use of 10% gum arabic and eugenol was effective, with antioxidant action in the colon, as well as reducing oxidative stress in all colon segments and preventing and treating genotoxicity in all colon segments. Furthermore, their joint administration reduced the number of aberrant crypts and the number of aberrant crypt foci (ACF) in the distal segment and entire colon, as well as the number of ACF with at least 5 crypts in the entire colon. Thus, our results also demonstrate the synergistic effects of 10% gum arabic together with eugenol (from cloves), with antioxidant, antigenotoxic and anticarcinogenic actions (prevention and treatment) at the doses and durations studied, in the colon of rats submitted to colorectal carcinogenesis induced by dimethylhydrazine.

高效液相色谱-串联质谱法测定玉米蛋白粉中黄曲霉毒素B_(1)测量不确定度评定

采用GUM法和Top-down法对高效液相-串联质谱法测定玉米蛋白粉中的黄曲霉毒素B_(1)测量不确定度进行评定。通过比较2种方法的评定过程和评定结果发现,Top-down法在简化评定步骤、保证评定结果可靠性的前提下,能够充分利用实验室检测数据和质量控制数据,引入检测人员变动、检测仪器更换等带来的不确定度,是一种客观、高效的不确定度评定方法,为饲料中黄曲霉毒素B_(1)检测数据准确溯源提供参考。

GUM评定数字式气压计不确定度的适用性验证

为确保数字式气压计测量不确定度的可靠性,需对现有的测量不确定度表示指南(GUM)评定数字式气压计不确定度的方法进行适用性验证。本文根据国际标准ISO/IEC Guide 98-3:2008附件1给出的蒙特卡洛法(Monte Corlo Method,简称MCM)验证方案,以PTB220型数字式气压计为研究对象,分别采用自适应MCM对GUM方法进行不确定度的评定;将评定结果对比求偏差;根据偏差值是否超限来判定GUM方法适用性。结果表明:所采用的自适应MCM通过迭代增加试验次数,实时判断试验统计意义上的稳定,能有效确保评定结果的可靠性,且仅通过2×10^(4)样本量,计算出对应的评定结果。通过将GUM评定结果与其对比求偏差,分析得出GUM在进行数字式气压计的不确定度评定时偏离程度超过规定范围,说明GUM未能通过验证,即GUM可能不宜适用于该仪器不确定度的评定。

Effect of Gum Arabic from Acacia senegal var. kerensis as an Improver on the Rheological Properties of Wheat Flour Dough

Dough improvers are substances with functional characteristics used in baking industry to enhance dough properties. Currently, the baking industry is faced with increasing demand for natural ingredients owing to increasing consumer awareness, thus contributing to the rising demand for natural hydrocolloids. Gum Arabic from Acacia senegal var. kerensis is a natural gum exhibiting excellent water binding and emulsification capacity. However, very little is reported on how it affects the rheological properties of wheat dough. The aim of this study was therefore, to determine the rheological properties of wheat dough with partial additions of gum Arabic as an improver. Six treatments were analyzed comprising of: flour-gum blends prepared by adding gum Arabic to wheat flour at different levels (1%, 2% and 3%), plain wheat flour (negative control), commercial bread flour and commercial chapati flour (positive controls). The rheological properties were determined using Brabender Farinograph, Brabender Extensograph and Brabender Viscograph. Results showed that addition of gum Arabic significantly (p chapati. These findings support the need to utilize gum Arabic from Acacia senegal var. kerensis as a dough improver.

Physico-Chemical, and Sensory Properties of Mayonnaise Substitute Prepared from Chia Mucilage (Salvia hispanica L.) and Gum Arabic from Acacia senegal var. kerensis

Gum Arabic (GA) from Acacia senegal var. kerensis has been approved as an emulsifier, stabilizer, thickener, and encapsulator in food processing industry. Chia mucilage, on the other hand, has been approved to be used as a fat and egg yolk mimic. However, both chia mucilage and gum Arabic are underutilized locally in Kenya;thus, marginal reports have been published despite their potential to alter functional properties in food products. In this study, the potential use of chia mucilage and gum Arabic was evaluated in the development of an eggless fat-reduced mayonnaise (FRM). The mayonnaise substitute was prepared by replacing eggs and partially substituting sunflower oil with chia mucilage at 15%, 30%, 45%, and 60% levels and gum Arabic at 3% while reducing the oil levels to 15%, 30%, 45%, and 60%. The effect of different concentrations of oil and chia mucilage on the physicochemical properties, for example, pH, emulsion stability, moisture content, protein, carbohydrate, fats, calories, ash, and titratable acidity using AOAC methods and sensory properties for both consumer acceptability and quantitative descriptive analysis of mayonnaise were evaluated and compared to the control with eggs and 75% sunflower oil. The results indicated that all fat-reduced mayonnaises had significantly lower energy to 493 kcal/100g and 20% fat content but higher water content of 0.74 than the control with 784 Kcal/100g calories, 77% fat and 0.39 moisture. These differences increased with increasing substitution levels of chia mucilage, as impacted on pH, carbohydrate, and protein. There was no significant difference between ash content for both fat-reduced mayonnaise and control. Sensory evaluation demonstrated that mayonnaises substituted with chia seeds mucilage and gum Arabic were accepted. All the parameters are positively correlated to overall acceptability, with flavor having the strongest correlation of r = 0.78. Loadings from principal component analysis (PCA) of 16 sensory attributes of mayonnaise showed that approximately over 66% of the variations in sensory attributes were explained by the first six principal components. This study shows good potential for chia mucilage and gum Arabic to be used as fat and egg mimetics and stabilizers, respectively, in mayonnaise with functional properties.

Continuous Gum Chewing Exercise Improves Perioral Muscle Strength

Objective: The purpose of this study was to examine the effects of continuous gum chewing exercise on perioral muscle strength. Methods: Thirty healthy adults (24.1 ± 2.0 years) with normal occlusion performed gum chewing exercise 3 times daily for 3 months. Each exercise session lasted 5 min and involved alternating of chewing 10 times using the left molars and then 10 times using the right molars, with the mouth closed. The effect of the exercise on oral function was evaluated by measuring tongue pressure (TP), cheek pressure (CP), and labial closure strength (LCS) immediately before starting exercise, at 2 weeks and 1, 2, and 3 months after starting exercise, and at 3 months after cessation of exercise. Changes in TP, CP, and LCS according to sex and duration of exercise were analyzed by repeated two-way ANOVA. Results: Measurements for all muscles were significantly greater in men than in women at all time points. After starting exercise, TP was markedly increased at 2 months in men and women, and both CP and LCS were markedly increased at 2 weeks in men and at 1 month in women. These effects persisted for 3 months. Three months after cessation of exercise, TP, CP, and LCS tended to decrease, but were not significantly attenuated as compared with 3 months after beginning of exercise in either sex. Conclusion: The results of this study revealed that gum chewing exercise contributed to an improvement in perioral muscle strength, and that this effect was maintained for at least 3 months after discontinuation of exercise.

氯化铵-乙醇交换法-等离子体发射光谱法测定石灰性土壤交换性盐基及盐基总量的不确定度评定

采用电感耦合等离子体发射光谱法对石灰性土壤(pH>7.5)交换性盐基(交换性钾、钠、钙、镁)及盐基总量的测定方法进行系统的不确定度分析,采用GUM法系统性判定整个过程不确定度的主要来源,同时对石灰性土壤盐基总量不确定度来源进行细化确认,对各类不确定度分量进行合成计算,得出合成标准不确定度、扩展不确定度及测定结果的置信区间,并依据各个分量不确定度对合成标准不确定度的贡献得到分析过程需重点控制的关键点。

等离子体发射光谱法测定土壤中有效硫不确定度评定

本文对电感耦合等离子体发射光谱法测定土壤中有效硫的不确定度来源及不确定分量进行了系统性的不确定度分析,并得出合成标准不确定度、扩展不确定度。依据GUM法对分析过程中不确定度的引入进行了详细阐述和计算,最终确定该分析方法的主要不确定度来源为标准曲线拟合引入的不确定度和试样测量重复性引入的不确定度,并总结了对应措施以减小引入的不确定度。