The effects of date syrup and guar gum on physical,rheological and sensory properties of low fat frozen yoghurt dessert

The effect of adding date syrup (0%, 25% and 50% as sugar replacement) and guar gum (0%, 0.1%, 0.2% and 0.3% as fat replacement) was examined in respect of physicochemical, rheological and sensory properties of low fat frozen yoghurt. Increasing date syrup and guar gum concentration increased the mixture viscosity and acidity. Guar gum softened the frozen yoghurt whereas date syrup increased the hardness of the product. The control yoghurt was less sticky than samples containing the gum, but date syrup had no significant effect on the samples stickiness. Melt‐down stability of the samples also increased with increase in gum and date syrup concentration. The low fat orange flavoured frozen yoghurt dessert prepared in this study also had good sensory properties.     

Influence of guar gum addition on physicochemical,microbial, rheological and sensory properties of stirred yoghurt

This study investigated the effects of adding guar gum (0, 0.6 and 0.8 g/100 mL) on the physicochemical, microbial, rheological and sensory properties of stirred yoghurt. Incorporation of guar gum into the yoghurt significantly affected the pH and colour, but did not significantly influence the lactic acid bacteria counts. The magnitudes of apparent viscosity (η_a,100), consistency index (K), yield stress (σ_oc), storage modulus (G′) and loss modulus (G″) for yoghurt samples containing guar gum (0.6–0.8 g/100 mL) were significantly greater than those for the control (without guar gum), indicating that guar gum can improve the steady and dynamic shear rheological properties of yoghurt.     

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。     

Influence of guar gum on the baking quality of gluten-free cheese bread made using frozen and chilled dough

The aim of the study was to assess the effect of guar gum on the quality and textural properties of gluten-free (GF) cheese bread made using chilled and frozen GF cheese dough. The guar gum addition was at 3.5% (G3.5), 4% (G4) and 4.5% (G4.5) levels, based on the weight of the cheese in the product. Samples of frozen dough with 3.5% guar gum and of chilled dough with 4.5% guar gum were chosen for sensory analysis as they had the closest hardness and specific volume to samples of fresh dough and dough without guar gum (Control). The overall consumer acceptance of samples that had been processed using freezing treatment presented the lowest liking score due to the light salty taste.     

Classification and physicochemical characterization of mesquite gum (Prosopis spp.)

Under environmental stress conditions, mesquite trees can excrete a proteinaceous arabinogalactan gum that is similar to gum arabic. Given the application potential of this type of gums a classification procedure for the mesquite gum is proposed. The main physicochemical properties of the best-quality mesquite gum were determined and compared with those of gum arabic. Additionally, the composition and molecular changes induced by purification processes were recorded. One batch (157 kg) of mesquite gum was categorized by subjective assessment into three classes (MGA, MGB and MGC) from high- to low-quality. Approximately 17.5% was classified as top-quality gum. It was found that this class of mesquite gum has lower humidity, inorganic and tannins content than the other classes, or even than the gum arabic sample used as a reference. All of the mesquite gum classes have higher protein content and lower intrinsic viscosity than gum arabic. The purification processes were shown to reduce the content of lower molecular weight compounds that modify the interface properties of the gum. The results indicate that the proposed classification method can be used to select mesquite gum with physicochemical properties comparable to those of commercial gum arabic.     

不同类型稳定剂和乳化剂对冰淇淋品质特性的影响

本文研究了不同类型的稳定剂和乳化剂在冰淇淋中的作用,以三种代表性的不同类型的稳定剂:卡拉胶（离子型多糖）、瓜尔豆胶（非离子型多糖）和明胶（蛋白质）,以及具有不同亲水亲油性的乳化剂:单硬脂肪酸甘油酯（Glyceryl Monostearate, MG,HLB=3.8）和吐温80（HLB=15）作为研究对象,以冰淇淋的物理特性（粘度、膨胀率与融化率）和感官（粘稠度、顺滑性、口融性与颗粒感）为指标,讨论了稳定剂和乳化剂对冰淇淋品质的影响。结果表明,与吐温80相比,加入MG的冰淇淋膨胀率更高,抗融性更好,二者对浆料粘度的作用无显著性差异（P<0.05）;三种稳定剂均可增大冰淇淋浆料的粘度,其中,卡拉胶较瓜尔豆胶和明胶对浆料粘度的影响差异显著（P<0.05）,抗融性最强,瓜尔豆胶对膨胀率影响最大。其中MG与卡拉胶复配所得浆料粘度和抗融性最佳,分别为898.35 cp,融化率4.74%;与瓜尔豆胶复配所得冰淇淋膨胀率最高为66.95%。在此基础上,以MG作为乳化剂,复配瓜尔豆胶和卡拉胶,研究不同复配比例的稳定剂在冰淇淋中的作用。结果表明,稳定剂总添加量为0.25%时,卡拉胶与瓜尔豆胶的质量比为1:1.5,冰淇淋的浆料粘度可达1036.5 cp,融化率为17.4%,感官评分最高。     

黄原胶和瓜尔豆胶的复配稳定剂对冰淇淋品质和流变性的影响

研究了黄原胶和瓜尔豆胶的复配胶作为冰淇淋稳定剂对冰淇淋品质和流变性的影响,测定了冰淇淋浆料的粘度,应用小幅振荡测定经硬化后冰淇淋成品的动态粘弹性,以及硬化冰淇淋的硬度和粘结度.结果表明,随复配胶用量的增加,冰淇淋浆料的粘度也随之增加,另外,Power law模型的流动指数和粘度指数、冰淇淋成品储能模量、及硬度、粘结度均呈增加趋势.实验结果还表明,随复配胶用量的增加,冰淇淋的弹性模量和稳定性得以提高.通过测定冰淇淋的膨胀率和抗融性,得出冰淇淋中复配胶的最佳添加量质量分数为0.35%.     

Rheological properties of whey protein isolate stabilized emulsions with pectin and guar gum

Dynamic oscillatory and steady-shear rheological tests were carried out to evaluate the rheological properties of whey protein isolate (WPI) stabilized emulsions with and without hydrocolloids (pectin and guar gum) at pH 7.0. Viscosity and also consistency index of emulsions increased with hydrocolloid concentration. At γ = 20 s⁻¹, the value of viscosity of the emulsion with 0.5% (w/v) pectin was about fivefold higher than that of the emulsion without pectin. Flow curves were analyzed using power law model through a fitting procedure. Flow behaviour index of all emulsions except for containing 0.5% (w/v) guar gum was approximately in the range of 0.9–1.0, which corresponds to near-Newtonian behaviour. The shear thinning behaviour of emulsions containing 0.5% (w/w) guar gum was confirmed by flow behaviour index, n, of 0.396. Both storage (G′) and loss modulus (G″) increased with an increase in frequency. Emulsions behaved like a liquid with G″ > G′ at lower frequencies; and like an elastic solid with G′ > G″ at higher frequencies. Effect of guar gum was more pronounced on dynamic properties. Phase angle values decreased from 89 to <10° with increasing frequency and indicated the viscoelasticity of WPI-stabilized emulsions with and without pectin/guar gum.     

Influence of pumpkin puree and guar gum on the bioactive,rheological, thermal and sensory properties of ice cream

The effects of pumpkin puree and guar gum on the bioactive, rheological, thermal and sensory properties of ice cream were investigated. The addition of pumpkin puree increased total phenolic content, dietary fibre, and antioxidant activity. Appropriate models described shear thinning and thixotropic behaviours of all mixes. By either adding pumpkin puree or by increasing guar gum concentration, all rheological properties increased except the flow behaviour index. Adding pumpkin puree reduced the freezing point temperature, ice content, frozen water and glass transition temperature but it increased unfreezable water. Increasing guar gum concentration did not alter colour and firmness, whereas the pumpkin puree increased colour, intensity of fruit flavours and firmness.     

Influence of selected hydrocolloids on triticale starch rheological properties

The aim of the study was to define the influence of selected nonstarch polysaccharides (guar gum, xanthan gum and arabic gum) on several rheological properties of triticale starch pastes/gels, at constant polysaccharide concentration (6.5 g/100 g). These included pasting characteristics, flow curves at 50 °C and mechanical spectra at 25 °C. It was found that the presence of a gum in a system modified the rheological properties of triticale starch gels/pastes, depending on the type and concentration of the gums. In the case of guar and xanthan gums, higher pasting viscosity was observed and the shear stress was increased compared with native starch. The presence of guar gum reduced the degree of thixotropy hysteresis, negative values for this being found for systems with xanthan in spite of their shear‐thinning behaviour. Systems containing arabic gum displayed lower values of pasting and flow viscosity. The type and concentration of gums added to the polysaccharide influenced the viscoelastic properties of the gels.     

魔芋胶、琼脂及他拉胶对软冰淇淋品质影响研究

对反应软冰淇淋品质的各指标进行测试,以考察魔芋胶、琼脂、他拉胶对软冰淇淋品质的影响.结果表明,在没有乳化剂存在情况下,三种稳定剂相比,琼脂对软冰淇淋浆料黏度和热稳定性基本无影响,对膨胀率、抗溶性和硬度起降低作用,但相对其他2种稳定剂而言抗融性最好,硬度最大;魔芋胶对软冰淇淋浆黏度起增大作用,提高膨胀率,但硬度和抗融性最差;他拉胶对冰淇淋浆料黏度的影响随添加量的增加缓慢增大,对膨胀率、硬度和抗溶性均由降低作用,但对各指标的影响程度稍好于魔芋胶.     

Effects of pectin and guar gum on creaming stability, microstructure and rheology of egg yolk plasma-stabilized emulsions

The influence of pectin and guar gum on the creaming stability, microstructure and rheological properties of 1.0% (w/v) egg yolk plasma (EYP)-stabilized 25.0% (v/v) soybean oil-in-water emulsions was studied at pH 7.0. Addition of pectin/guar gum decreased creaming percentage, and no creaming was detected in the presence of 0.5% (w/v) pectin/guar gum as a result of increasing viscosity. At the end of 10 h, creaming percentage decreased from 61 to 57% with the addition of 0.05% (w/v) guar gum and to 39% with the addition of 0.2% (w/v) guar gum. Microscopic observations represented the droplet aggregation arising from the presence of nonabsorbing biopolymers. At \mathop g^. \mathop \gamma \limits^{.}  = 10 s⁻¹, a tenfold increase in viscosity was observed in the presence of 0.5% (w/v) guar gum compared to the presence of 0.1% guar gum due to the thickening effect of polysaccharide. Increasing gum concentrations enhanced the viscosity and hence the consistency index. All emulsions, except for those containing 0.5% (w/v) guar gum, reflect the near-Newtonian behaviour with flow behaviour index, n, of 0.9–1.0. All emulsions exhibited a liquid-like behaviour at low frequencies (<7.0 Hz) where G″ values were higher than G′. Both G′ and G″ showed a frequency dependency and these two moduli crossed each other at higher frequencies (>7.0 Hz), G′ became greater than G″ and the system behaved like an elastic solid. Addition of pectin at all levels cause no significant change in G′ and G″ values, whereas addition of guar gum, especially at a concentration of 0.5% (w/v), significantly improved these values.     

Effects of batters containing different gum types on the quality of deep‐fat fried chicken nuggets

The effects of various gum types [hydroxypropylmethylcellulose (HPMC), guar gum, xanthan gum, gum arabic] on the quality of deep‐fat fried chicken nuggets were studied. Chicken samples, 0.04 m in diameter and 0.015 m in thickness taken from the breast portion, were coated with batters composed of a 3:5 solid to water ratio by immersion. The solid content of batter formulations contained equal amounts of corn and wheat flours, 1.0% gum, 1.0% salt and 0.5% leavening agent. As control, batter without gum addition was used. Samples were fried at 180 °C for 3, 6, 9 and 12 min. The hardness and oil content of the chicken nuggets increased whereas the moisture content decreased during frying. HPMC and xanthan gums reduced oil absorption significantly compared with other gums and the control. When gum arabic was added to the batter formulation, a product with the highest oil content and porosity was obtained. Copyright © 2005 Society of Chemical Industry     

The Relationship Between Wheat Flour and Starch Pasting Properties and Starch Hydrolysis: Effect of Non‐starch Polysaccharides in a Starch Gel System

Non‐starch polysaccharides (NSPs) and celite (used as inert filler) were incorporated into wheat flour and wheat starch paste preparations at levels of 1, 2.5, and 5% in both addition and replacement modes. Pasting properties of gums were compared using a Rapid Visco Analyser. Use of guar gum and locust bean gum elevated the peak and final viscosities of the resulting pastes (when used in either addition or replacement modes), whereas arabic gum significantly reduced the peak and final viscosity properties of the pastes. Samples which comprised wheat starch yielded higher peak and final viscosity characteristics compared to wheat flour containing samples, however higher breakdown and setback values were observed for samples using wheat flour as a base compared to wheat starch. The firmness of the gels (as determined using a texture analyser) increased with the use of wheat starch compared to wheat flour. Little significant difference was observed between NSP used and mode of application (replacement or addition). In vitro starch degradation was conducted on the wheat flour gels. Guar gum and locust bean gum reduced the amount of starch degradation in these gels, whereas arabic gum and celite increased the amount of starch hydrolysis (or were similar to the control). The rate of starch hydrolysis appears to be related to the viscosity altering behaviour of the NSPs in a starch‐rich system. The results indicate that selection of NSPs is important as gum arabic has the potential to increase starch hydrolysis compared to the control.     

黄原胶与魔芋胶混胶黏度的影响因素研究

黄原胶和魔芋胶都是非凝胶多糖，二者在一定条件下共混可以出现强烈的协同效应。本文研究当黄原胶和魔芋胶以5／5的配比共混，总浓度为1％，温度，柠檬酸，蔗糖和功能型甜味对混胶多糖黏度的影响。结果表明：升高温度使混胶的黏度降低；当柠檬酸的使用量大于0．2％时，混胶的黏度下降；40℃时甜味剂的加入使得混胶的黏度升高。     

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.     

Interfacial adsorption and shear flow properties of gum arabic-sodium caseinate mixtures

This work discusses rheological and physicochemical properties of sodium caseinate and gum arabic, in aqueous media (25 °C). All the systems showed low viscosity values and Newtonian behaviour in the shear rate range studied. From particle size distribution, a limited thermodynamic compatibility was observed since hydrocolloids mixtures showed particles size between the values from the systems alone. Interfacial tension measurements at equilibrium at the air-water interface, revealed that the binding affinity of arabic to the air water interface is very low compared to that of caseinate. The adsorption critical concentration could be deduced as a function of aqueous solutions composition. In competitive adsorption experiments involving simultaneous adsorption of the hydrocolloids from a bulk mixture, sodium caseinate displaced gum arabic from the interface at both polysaccharide concentrations, changing the adsorption critical concentration.     

Preparation of resistant starch from starch–guar gum extrudates and their properties

Mixtures of starch, guar gum and citric acid were extruded at a temperature of 150 °C and screw speed of 180 rpm. Properties of the extrudates such as bulk density, expansion ratio, apparent viscosity and resistant starch content were measured with different concentrations of guar gum. Extrusion with citric acid influenced the physical properties and resistant starch content of the extrudate. Expansion ratios were lower for samples extruded with citric acid, and decreased as starch–gum concentration increased. The apparent viscosity of the extrudate increased with increasing guar gum concentration; however, citric acid at 2.0% concentration was found to lower the viscosity of the extrudate. Resistant starch content increased from 6.23% for extruded starch only to 14.21% for starch–gum extrudate, and further enhanced to 16.19% with the addition of 2.0% citric acid to the starch–gum extrudate. Resistant starch increased with increase of gum concentration and decreased with increase of starch–gum concentration from 7.5% to 12.5%.     

Semi‐dilute solutions of hydroxypropyl guar gum: Viscosity behaviour and thixotropic properties

Semi‐dilute solutions of hydroxypropyl guar gum (HPGG), the most widely used derivative of naturally occurring guar galactomannan, were investigated with respect to their viscosity, yield stress and thixotropy. It was found that the shear‐dependent viscosity behaviour under various HPGG concentrations, added salts and temperature could be well described by the Cross viscosity model. The zero‐shear‐rate viscosity was observed to change with HPGG concentration according to a power‐law function, and decease with the increase of temperature according to an Arrhenius‐type equation. The addition of salts (KCl and CaCl₂) lowered the zero‐shear‐rate viscosity. The HPGG solutions of high concentration showed a higher degree of thixotropy while the addition of salt lowered the thixotropic property. Copyright © 2007 Society of Chemical Industry