食用胶对西式火腿物性特性的影响

探讨以猪肉为原料的西式火腿加工过程中,食用胶加入的种类、加入方式和加入量对产品物性的影响,并采用正交试验研究不同食用胶在西式火腿中的应用效果。结果表明,卡拉胶的加入对西式火腿的黏着性、凝聚性、弹性均有较好影响,当以单一的食用胶添加在西式火腿中时,使用卡拉胶且以粉状的方式添加以及添加量为0.3% 时的效果为最佳。     

Functionality of medium molecular weight xanthan gum produced by Xanthomonas Campestris ATCC 1395 in batch culture

Xanthan gum of medium molecular weight was produced by Xanthomonas Campestris ATCC 1395 in a laboratory fermenter without pH control by applying a stirrer speed of 600 rpm and its stabilization properties in salad dressing emulsions were evaluated. The gum performed satisfactorily as an emulsion stabilizer and thickener although it had to be used in higher concentrations in order to be as effective as the commercially available xanthan gum. Furthermore, resilient gel structures resulted when the gum was used in an admixture with locust bean gum. The gel texture profile was different compared to that of the commercial sample/locust bean gum mixture, suggesting that the gum could present an alternative for the preparation of gels of acceptable textural properties.     

Effects of food gums and pre-drying on fat content of fabricated fried chips

Deep-frying contributes to the unique taste and texture of fried products. However, they are low in nutritional value. Food industries actively trying to find ways to reduce the fat content while maintaining organoleptic properties of fried foods. In this work, effects of pre-drying and adding food gums on the moisture and fat contents of chips were evaluated. The chips were pre-dried for 60 and 90 min, and gellan gum, guar gum, methylcellulose and xanthan gum were added at the concentration of 0.25, 0.75, 1 and 2 % w/w. The xanthan gum was the most effective gum for fat reduction. The addition of 0.25 % w/w xanthan gum and at 90 min pre-drying reduced the fat content from 20 % (control) to 15 % w/w. The results also indicated that the reduction of moisture content after frying was not affected by the type of gums but the method of pre-drying.     

黄原胶对酪蛋白酸钠乳状液稳定性的影响

研究了一定pH条件下,黄原胶浓度及剪切稀化效应对酪蛋白酸钠乳状液稳定性的影响。结果表明,在酸性条件下,黄原胶无法抑制酪蛋白的变性沉淀,乳液在制备之初,即产生严重絮凝。在中性和弱碱性条件下,黄原胶在一定浓度范围内,诱发了乳状液的排斥絮凝;体系的pH显著影响了乳状液的稳定性,pH6条件下,较低的黄原胶浓度(0.2wt%)便可赋予乳状液良好的稳定性。均质过程大大降低了黄原胶的粘度,导致乳状液的稳定性下降,与添加未经均质处理的黄原胶相比,添加量增大近一倍,才能获得稳定的乳状液。     

食用胶对重组牛肉加工特性的影响

将转谷氨酰胺酶和酪蛋白酸钠作为重组牛肉使用的黏合剂,添加量为原料牛肉质量的1.2%。在此基础上,分别添加0.3%(m/m)的卡拉胶、亚麻胶等多种食用胶,通过测定黏结性、色差、解冻损失、蒸煮损失、尺寸变化、剪切力、质构来说明食用胶对重组牛肉加工特性的影响。研究结果表明,亚麻胶和黄原胶都显著降低了重组牛肉的黏结性(P ＜ 0.05),且成片性不好。卡拉胶能增加a* 值,δ- 葡萄糖酸内酯(GDL)和卡拉胶的复合胶却降低了a* 值。添加结冷胶、亚麻胶和黄原胶均降低重组肉的解冻损失和蒸煮损失,而且添加亚麻胶和黄原胶的重组牛肉嫩度最大。     

盐及非盐物质对常用低浓度食品胶溶液粘度影响的研究

对饮料生产中常用的食品胶－黄原胶、海藻酸钠、瓜尔胶和琼脂在低浓度水相体系中外加盐（阴、阳离子）、乙醇、蔗糖及柠檬酸对溶液粘度的影响作了探讨性研究,结果表明四种胶溶液（０．１０％黄原胶、０．３０％海藻酸钠、０．２５％瓜尔胶、０．１０％琼脂）中、瓜尔胶溶液对盐的耐受性最好,即大多数阴阳离子都不会对其粘度产生影响,而常用金属盐阳离子及Ｃｌ＾－、ＳＯ３＾２－对黄原胶溶液粘度的影响与阴阳离子对海藻酸钠和琼脂     

Physical and Oxidative Stabilities of O/W Emulsions Formed with Rice Dreg Protein Hydrolysate: Effect of Xanthan Gum Rheology

The shortening of shelf-life of food emulsions is frequently due to poor creaming and lipid oxidation stability. The lipid oxidation of O/W emulsions can be inhibited by rice dreg protein hydrolysate (RDPH); however, emulsions were stabilized by Tween-20. Polysaccharides can control the rheology and network structure of the aqueous continuous phase by increasing viscosity and yield stress, hence retarding phase separation and gravity-induced creaming, especially for xanthan gum. The objective of this research was to evaluate whether emulsions formed with 2 wt% RDPH and stabilized by xanthan gum (0–0.5 wt%) could produce 20 % (v/v) soybean oil-in-water emulsions that had good physical and oxidative stability. The degree of flocculation of droplets as a function of xanthan gum concentration was assessed by the microstructure, rheology, and the creaming index of emulsions. Addition of xanthan gum prior to homogenization had no significant effect on the mean droplet diameter in all emulsions studied. Increase in xanthan gum concentration led to the increase in creaming stability of emulsions, due to an increase in viscosity of the continuous phase and/or the formation of a droplet network with a yield stress, as well as the enhanced steric and electrostatic repulsion between the droplets. Lipid oxidation of the emulsions was significantly inhibited at xanthan gum concentrations of 0.12 wt% or above with RDPH, which could due to the fact that xanthan gum increases the viscosity of the aqueous phase and hindered the diffusion of oxidants to the oil droplet surface area, synergistic effect between RDPH and xanthan gum to suppress oil peroxidation, and metal ion chelation capability of xanthan gum. Thus, stable protein hydrolyzates-type emulsions could be obtained with increasing concentration of xanthan gum.     

Influence of pH and added gums on the properties of konjac flour gels

The gel strength and texture of konjac gel and mixed gels of konjac and various gums were measured after gelation at various concentrations of alkali. A selection of different alkaline reagents was used. Regardless of alkali concentration, increasing konjac levels caused a decrease in pH but an increase in hardness and strength of konjac/gellan gum mixed gels. The highest gel strength and hardness were given by mixed konjac/gellan gum gels using sodium carbonate as the gelling medium. Under similar gelling conditions, the addition of gellan gum resulted in the greatest gel hardness. Of the gums examined, a possible synergistic effect on konjac/gellan gum mixed gel texture was observed.     

Production of reduced-calorie grape juice jelly with gellan, xanthan and locust bean gums: sensory and objective analysis of texture

 The production of reduced-calorie grape juice jellies with gellan, xanthan and locust bean gums (LBG) was studied. Twenty formulations of grape juice jelly were prepared according to a second-order composite rotatable design (with six central points). Response surface methodology (RSM) was used to optimise jelly formulation using as independent variables: total sugar content, ranging from 14 to 46°Brix; and total gum concentration ranging from 0.30 to 0.70% (w/v), with the proportion of gums in the mixture xanthan:LBG:gellan ranging from 5:5:90 up to 45:45:10. The processing temperature used was 90°C for complete solubilisation of gums. The dependent variables were objective measures of texture and a parameter obtained from sensory analysis, the overall balance (B), which represents the overall evaluation of the jelly. The resulting polynomial equation (R ² = 0.929) revealed that a jelly produced with white grape juice, total sugar with sucrose equal to 39.3°Brix, and, 0.54% (w/v) of total gum added in the proportions of: 1:1:1.7 (gellan:xanthan:LBG) had a maximum value of B. The sensory-optimised jelly was objectively characterised for texture and the model was tested. The texture characteristics, i.e. gel hardness, cohesiveness and springiness, were found to be similar to those of a reference product, a previously developed reduced-calorie grape juice jelly with low methoxyl pectin. Received: 12 June 1997 / Revised version: 21 August 1997     

Application of decolourised hsian‐tsao leaf gum to low‐fat salad dressing model emulsions: a rheological study

The effects of mixed gums, including decolourised hsian‐tsao leaf gum (dHG) mixed with propylene glycol alginate (PGA) or xanthan gum (XG), and egg yolk concentration on the rheological properties of low‐fat salad dressing model emulsions were studied. All model emulsions showed pseudoplastic flow behaviour. Model emulsions with PGA addition showed the lowest pseudoplasticity, followed by those with dHG and then XG addition. Increasing the PGA level in the dHG/PGA system reduced the pseudoplasticity. Increasing the XG level in the dHG/XG system did not change the pseudoplasticity significantly but imparted a significant increase in viscosity. Dynamic viscoelasticity measurements indicated that model emulsions with dHG or XG addition could be classified as elastic gels. However, model emulsions with PGA addition essentially belonged to the class of either dilute or concentrated solutions rheologically, depending on the egg yolk concentration. The rheological characteristics of individual gums were found to be confounded in generating the rheological characteristics of model emulsions containing them. Copyright © 2004 Society of Chemical Industry     

Volatilities of Short-Chain Fatty Acids in a Fermented Milk Model System as Affected by Stabilizers

A fermented milk model system was employed to investigate the volatilities of butyric, caprylic, and caproic acids as affected by low, intermediate, and high levels of carrageenan, guar and xanthan gums. Carrageenan exhibited no effect on fatty acid volatility. Intermediate levels of guargum increased the volatility of caprylic acid. Low and high levels of guar gum had no effect on free fatty acid volatility. At low and high levels, xanthan gum had no effect on volatilities of fatty acids. The intermediate level of xanthan gum increased volatilities of caproic and caprylic acids. The effects of viscosity were potentiated with increased fatty acid chain length.     

Properties of Algin/Calcium and Salt/Phosphate Structured Beef Rolls with Added Gums

Ten polysaccharide gums at two levels (0.5 and 1.0%) were individually incorporated into algin/calcium (AC) and salt/phosphate (SP) structured beef rolls (<6% fat) prepared with 15 and 30% added water. Cook yield, pH, bind and textural properties were evaluated. Each gum had specific effects on properties of beef rolls. For example, kappa-carrageenan improved (P<0.001) cook yields and maintained or improved bind and texture of raw and cooked samples of both meat binding systems. Cook yields of AC products were improved with gellan gum, while yields of SP products were improved with iotacarrageenan. Other gums (xanthan, guar, pectin, carboxymethyl cellulose) improved water holding (cook yields) but had detrimental effects on product texture.     

Characterization of emulsion stabilization properties of quince seed extract as a new source of hydrocolloid

The capability of seed extracts in stabilizing emulsions has particularly received interest in recent years. Upon soaking quince seeds into water, biopolymers inside the seeds are extracted to water, forming mucilage. This study investigates the physical stability, rheology and microstructure of oil (sunflower oil) in water emulsions, stabilized by 2% (w/v) whey protein isolate with varying concentrations of xanthan and quince seed gum. Quince seed gum resulted in emulsions with smaller low-shear viscosities and shear thinning capabilities compared to the same concentrations of xanthan. Quince seed gum emulsions with concentrations ≤ 0.1 (w/v), displayed rapid creaming due to bridging flocculation. Despite the difference in apparent viscosities, for gum concentrations < 0.2 (w/v), both gums demonstrated comparable stability with xanthan gum in general yielding marginally more stable emulsions. Gum concentrations > 0.3 (w/v) resulted in physically stable emulsions even after 5 months. Overall, quince seed gum displayed significant emulsification and stabilization properties.     

Viscoelastic characterization of fluid and gel like food emulsions stabilized with hydrocolloids

Food emulsions exhibit a great diversity of rheological characteristics; hydrocolloids are usually added to deal with creaming instability. Viscoelastic measurements provide information about the microstructure of the system. The objectives of this work were: a) to determine the viscoelastic behavior of two different low in fat oil-in-water food emulsions: a gel like and a fluid type emulsions stabilized with hydrocolloids (gellan gum and xanthan-guar mixtures respectively) b) to model and predict the mechanical relaxation spectrum for both emulsions and continuous aqueous phases. Low-in-fat oil-in-water emulsions (20 g/100 g) were prepared using sunflower oil and Tween 80 (1 wt.%). Fluid emulsions containing xanthan and guar gums were formulated using a synergistic ratio 7:3, with total hydrocolloid concentration ranging between 0.5 to 2 wt%. The aqueous phases contained NaCl (2 wt.%) and acetic acid (2 wt.%). The effect of hydrocolloids was studied using oscillatory measurements (G’ and G” vs. frequency) within the linear viscoelastic range previously determined by stress-sweeps. Time-Concentration Superposition principle was applied to find the master curves that describe the mechanical spectra of the viscoelastic materials. Superposition allows to obtain a wide spectrum of nearly ten decades of frequencies in emulsions containing xanthan–guar mixtures, whereas gellan gum systems did not show a significant frequency displacement. Viscoelastic behavior of the systems was satisfactorily modeled using Baumgaertel-Schausberger-Winter (BSW) equation. This empirical model was used to predict the mechanical relaxation spectrum for both emulsions and continuous aqueous phases. Validation of the predicted spectra was carried out through creep compliance data for emulsion-filled gels and steady-state flow curves for emulsions containing xanthan–guar mixtures.     

Effect of modified Acacia gum (SUPER GUM™) on the stabilization of coconut o/w emulsions

Two modified Acacia gums, the already tested SUPER GUM? EM2 and the new EM10, were used as combined emulsifiers and stabilizers in coconut oil model emulsions. The properties of gum solutions as well as those of the emulsions were examined. The gum solutions were completely mechanically stable during high-pressure homogenization; therefore, the gum could be added to the emulsion prior to high-pressure treatment. The emulsions were prepared by a small-scale rotor-stator process and by high-pressure homogenization, respectively. Droplet size, stability and rheological properties of the emulsions were examined. As expected, the high-pressure process was very effective. The emulsions made with both modified gums had a droplet size below 1 μm and were completely stable for at least 7 weeks at up to 30 °C. The new SUPER GUM? EM10 was more efficient as an emulsifier than EM2; the droplet size distribution was more homogenous. All emulsions proved to be low-viscous and nearly Newtonian liquids. It can be concluded that the emulsion stability was mainly a result of the excellent emulsifying properties and not of an additional thickening effect of the gums. The modified Acacia gums can be recommended as an emulsifier and stabilizer for application in different food products, preferably in low-viscous emulsions such as coconut milk drinks or other beverages.     

魔芋胶-黄原胶复配体系流变学特性及其凝胶形成动力学分析

为探究魔芋胶与黄原胶2 种食品胶复配使用后的协同作用,以魔芋胶和黄原胶为原料,控制总凝胶质量分 数为1%,以魔芋胶与黄原胶质量比分别为2∶8、4∶6、5∶5、6∶4、8∶2进行复配后,考察复配体系的流变学特性并对 其凝胶形成进行动力学分析。结果表明：魔芋胶-黄原胶复配体系具有假塑性,当魔芋胶的添加比例逐渐增大时, 复配体系黏度系数K增大,流体系数n减小,且复配体系的动态黏弹性质也随着魔芋胶与黄原胶的质量比不同而改 变,当魔芋胶与黄原胶质量比为6∶4时,复配体系的K值达到最大、n值最小,具有最强的假塑性及黏弹性。同时, 魔芋胶与黄原胶的不同质量比对凝胶形成速率有较大影响,当质量比小于6∶4时,凝胶形成显示出较慢的速率,且 形成的凝胶强度较弱;当质量比为6∶4时凝胶形成速率加快,SDRa曲线和G’曲线上升明显,形成的凝胶强度增大, 当质量比继续增加时,凝胶形成速率反而降低。采用阿伦尼乌斯方程对凝胶形成过程中的动力学参数进行拟合,决 定系数均在0.98以上,表现出较高的拟合精度;凝胶形成过程中的活化能在魔芋胶与黄原胶质量比为6∶4时有显著 增加（P＜0.05）,高温段与低温段间的活化能也表现出明显差异。     

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.     

面筋蛋白粒子-黄原胶Pickering乳液的制备及其表征

制备黄原胶与面筋蛋白纳米粒协同稳的Pickering乳液,表征Pickering乳液的物理化学性能和微观结构。结果显示：通过黄原胶与面筋蛋白纳米粒协同作用,可制备出稳定性较好的Pickering乳液。低质量分数的黄原胶（0.2%）会促进乳析;当黄原胶质量分数不小于0.3%时,乳液于4 ℃贮存30 d仍无乳析现象;当黄原胶质量分数为1%时,贮存30 d乳液出现析油的现象。不同乳化顺序得到乳液的稳定性不同。乳液M-WG-XG（面筋蛋白纳米粒与玉米油乳化得粗乳液,然后加入黄原胶二次分散）的稳定性最好,同时乳液的平均粒径最小（21.4±0.314）μm。黄原胶的加入增大了乳液的净电荷,乳液的稳定性提高。共聚焦显微镜结果表明,乳液M-WG-XG液滴分布均匀,界面层呈现出多层结构。相比于其他方式制备的乳液,乳液M-WG-XG有更好的黏弹性和离子稳定性。     

Comparison of the effects of gums on dynamic rheological properties of acetylated sweet potato starch

Dynamic rheological properties of acetylated sweet potato starch (ASPS) pastes mixed with 3 commercial gums (guar gum, locust bean gum, and xanthan gum) were investigated at different gum concentrations. The dynamic moduli of the ASPS-gum mixtures were higher than those of the control, and they increased with an increase in gum concentration. In particular, the G′ value of xanthan and G″ value of guar gum at a 0.6% gum concentration were much higher as compared to those of other mixtures. Tan δ values of ASPS-xanthan mixtures were much lower than those of other samples, indicating that the elastic properties in the ASPS-gum mixture systems were strongly affected by the additions of xanthan. These results suggest that the presence of gums in ASPS modifies the viscoelastic properties, and that these modifications are dependent on the gum type and gum concentration.     

Rheological properties of aqueous blends of high purity barley β-glucan with high purity commercial food gums

Rheological properties such as flow behaviour, viscosity, viscoelasticity, and thixotropy of solutions of β-glucan purified from barley fibre concentrate and twelve commonly used food gums, alone and in combinations, were characterised using an oscillatory rheometer. Pure gums and gum combinations were evaluated at 0.5% and 0.75% (w/w) total gum concentration in aqueous medium, whereas the β-glucan/gum ratios were kept at 90/10 or 80/20 (w/w). Viscosity synergism was observed for β-glucan solutions in combination with xanthan, iota-carageenan, and carboxymethyl cellulose. However, barley β-glucan blends with lambda-carageenan, Konjac, high- and low-methoxyl pectin, microcrystalline cellulose, alginate, and gum arabic showed marked lowering of the viscosity compared to β-glucan alone. In addition, β-glucan/xanthan gum blends demonstrated improved shear tolerance compared to xanthan dispersions alone, and soft gel transformation. Non-thixotropic behaviour was observed for 0.5 and 0.75% (w/w) β-glucan dispersions and its gum combinations. None of the gum combinations studied demonstrated thixotropy.