Kinetic model for water/oil absorption of mesquite gum (Prosopis juliflora) and gum arabic (Acacia senegal)

The water and oil uptake of mesquite and arabic gums in powdered form was studied at temperatures of 23, 35 and 45°C. A previously proposed equation to predict osmotic equilibrium was tested using the experimental data with both gums and a good statistical fit was obtained. Mesquite gum showed the highest water and oil absorption at all temperatures studied. Temperature dependence of the reciprocal of the S₁ and WL_∞ were determined using an Arrhenius equation. The activation energy for water and oil absorption for gum arabic was 21.98 and 39.57 kJ mol⁻¹, compared to that of mesquite gum having values of 15.79 and 46.16 kJ mol⁻¹, respectively. A second order kinetic model was obtained for water and oil absorption for both gums.     

The emulsifying properties of Persian gum (Amygdalus scoparia Spach) as compared with gum Arabic

The current study compares the emulsifying properties of Persian gum (PG) and gum Arabic (GA) in emulsions. The effects of concentration (0.5–3% w/v PG, 2.5–15% w/v PG), pH (2–7), ionic strength [NaCl, CaCl₂ (0–300 mM)], and temperature (40–90°C) were investigated. The surface–volume mean diameter (D₃₂) of the emulsions showed that the minimum values were 9.89 ± 0.68 and 4.52 ± 0.03 µm for emulsions containing 1.5% w/v PG and 15% w/v GA, respectively. In addition, the zeta potential of PG and GA emulsion changed from ?23.5 to ?39.5 and ?30.5 to ?46.0 mV, respectively. The interfacial tensions of PG and GA emulsions were varied in the ranges of 34.0–15.0 and 29.0–9.0 mN/m, respectively. Changes in the D₃₂ value of GA emulsions showed were not significantly different (p > 0.05) with respect to the effects of pH, NaCl, CaCl_2, and temperature. The NaCl concentration had no significant effect on D₃₂; but its value decreased from 13.11 to 5.70 µm as the CaCl₂ concentration increased. The interfacial tension of PG significantly increased with decreasing pH 7–2 and increasing 0–300 mM salts. After heating (25–90°C), the D₃₂ values of PG and GA emulsions changed to 11.04–14.54 and 4.21–4.21 μm, respectively. The results of this study can be useful for the application of PG as an emulsifier in beverage emulsions.     

携氧剂(正十二烷)对黄原胶发酵的影响

黄原胶(XanthanGum)是由野油菜黄单胞菌(Xanthomonascampestris)以碳水化合物为主要底物,经发酵产生的一种酸性胞外杂多糖。其发酵中后期黏度增大,氧的溶解能力下降,从而影响了黄原胶的产量。研究黄原胶生物合成过程中,烷烃对提高供氧、提高产胶率的影响,同时电镜观察不同发酵时期野油菜黄单胞菌的产胶情况。试验结果表明:8%为最适正十二烷添加量,产胶率达4.16%而对照样仅为2.15%。     

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.     

Extraction methods and some physical properties of mesquite (Prosopis chilensis (Mol) Stuntz) seed gum

To evaluate the potential use of mesquite (Prosopis chilensis (Mol) Stuntz) seed gum, the behaviour of the gum was studied using two extraction methods (alkaline and acid), different pH values, two concentrations (0.2 and 0.4% w/v) and different temperatures. The capacity of the gum to stabilise food foams was also evaluated. The alkaline extraction yield (24.9%) was higher than the acid extraction yield (17.7%). Owing molecular to hydrolysis caused by the acid, acid extraction resulted in a lower protein content. Gum from acid extraction had a higher viscosity than that from alkaline extraction at all temperatures investigated (10, 20, 30, 40, 50 and 60 °C). There were no significant differences between the viscosities of mucilage dispersions at the different values of pH studied (3.0, 4.0 and 5.0). The addition of extracted mesquite gum (obtained by either method and at either concentration studied) to egg white foam provided a higher stability and decreased the liquid drainage and collapse of the foam. Copyright © 2004 Society of Chemical Industry     

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.     

Determination of galactomannan (gum) in guar (Cyamopsis tetragonolobus) by high performance liquid chromatography

A method is described for analysis by HPLC of galactomannan (gum) in seed of guar (Cyamopsis tetragonolobus (L) Taub). The dry seed is ground in 950 ml litre^?1 ethanol, and free sugars are removed by ethanol extract; the seed residue is hydrolysed with 2 M trifluoracetic acid in a pressure cooker (1 h at ? 105 kPa). Hydrolysing the gum in situ avoids the problems common with other techniques of extracting different fractions of gum, each having different mannose: galactose ratios. The method serves as a simple measure of gum contents in guar, and up to 20 samples per day can be processed.     

New studies on gum ghatti (Anogeissus latifolia) part I. Fractionation,chemical and physical characterization of the gum

This paper describes the fractionation, chemical and physical characterization of processed gum Ghatti (Gatifolia SD), and identifies the source of its surface activity. Four fractions were separated using the gradual ethanol precipitation method. With the increase of alcohol concentration, the chemical composition of the fractions exhibited a pattern: arabinose content increased, but the galactose, protein and uronic acid contents decreased in the order of: F50 (50% ethanol precipitate), F65 (65% ethanol precipitate), F80 (80% ethanol precipitate) and FS (the supernatant after 80% ethanol precipitation). Rheologically gum ghatti and its fractions exhibited Newtonian flow behavior until gum concentrations reached to 20% (w/v), at which point gum ghatti showed some shear thinning. At the same shear rate and concentration, the apparent viscosities of these fractions decreased in the order: F50 > F65 > F80 > FS. When compared at same concentration, the FS fraction had the highest surface activity relative to the Gatifolia SD, the other fractions and even gum Arabic. Monosaccharide composition and preliminary structural analysis showed that the branching of the polymer increased in the order of F50, F65 and F80. The degree of branching levels, protein and uronic acid content could be responsible for the different solubility of the fractions in alcohol. However, the molecular structure of FS is significantly different from the other fractions. FT-IR spectroscopy revealed no esterified carboxyl group in gum ghatti. Detailed structural elucidation of each fraction will follow.     

胶基糖中的香精应用和胶基糖配方

介绍胶基糖对香精香料的要求,胶基糖的香味评价,香精对胶基糖生产的影响,胶基糖香精的质量问题和可能原因分析,香精水溶性的快速测定,一些胶基糖配方的设计思路和一些花色品种的研发创意。     

胶基糖中的香精应用和胶基糖配方

介绍胶基糖对香精香料的要求,胶基糖的香味评价,香精对胶基糖生产的影响,胶基糖香精的质量问题和可能原因分析,香精水溶性的快速测定,一些胶基糖配方的设计思路和一些花色品种研发创意。     

Extraction and physicochemical characterisation of polysaccharide gum from Yanang (Tiliacora triandra) leaves

Yanang (Tiliacora triandra) is a vegetable used in many cuisines of the northeast of Thailand and Lao People’s Democratic Republic. This paper reports the optimised extraction and some physicochemical characteristics of polysaccharide gum from Yanang leaves. The optimised extraction condition was at the leaf:water ratio of 1:6.6, 85 °C, and 100 min extraction time. The major monosaccharide constituent of Yanang gum was xylose, together with substantial amounts of other neutral sugars. The FT-IR spectra of Yanang gum were similar to that of xylan. Yanang gum exhibited shear-thinning flow behaviour and the extent of shear-thinning was concentration dependent. The mechanical spectra of Yanang gum at low concentration (0.5%) were typical of semi-diluted to concentrated solutions. However, with increasing concentration, the solution behaved like a weak gel.     

结冷胶与卡拉胶/魔芋胶的复配机理研究

本文主要研究了不同KC、lNaCl浓度对结冷胶、κ-卡拉胶、魔芋胶复配体系凝胶强度的影响。实验结果显示:在一定浓度范围内,KCl使结冷胶与卡拉胶复配体系的凝胶强度基本为两者单体自身的凝胶强度之和,而NaCl则使两者具有一定的协同作用。魔芋胶与卡拉胶的协同作用是建立在卡拉胶先形成有序结构的基础上。通过对实验结果的分析,提出了结冷胶与卡拉胶/魔芋胶复配体系可能的凝胶协同机理。     

On the stabilization mechanism of Doogh (Iranian yoghurt drink) by gum tragacanth

Serum separation in Doogh, a favorite acidic dairy drink in the Middle East, is a major problem which happens due to low pH (≤4.00) and aggregation of caseins. Therefore, in the present study the influence of gum tragacanth (GT) and its soluble and insoluble fractions on prevention of serum separation as well as stabilization mechanisms were investigated using rheological, zeta potential and microscopic measurements. According to our findings, the soluble tragacanthin (T) and GT prevented serum separation at concentrations of 0.100 and 0.200%, respectively. Furthermore, the proper rheological model for control was Newtonian whereas for the others it was Power law. Based on viscoelastic experiments, Dooghs containing T and GT exhibited dominant viscose and elastic behaviors, respectively. In addition, the presence of T and GT changed the zeta potential values from positive to negative. It was elucidated that T adsorbs onto casein and induces stabilization via electrostatic and steric repulsions. Moreover, the insoluble bassorin (B) may assist stabilization by increasing the viscosity.     

Moisture adsorption isotherms of guar (Cyamposis tetragonoloba) grain and guar gum splits

Moisture adsorption isotherms of guar grain and guar gum splits were determined at 10, 20, 30 and 40 °C and 23-96% relative humidities using gravimetric method. The sorption data were fitted to six well-known sorption isotherm models (modified Chung-Pfost, modified Halsey, modified Henderson, modified Oswin, Chen-Clayton, and GAB models) using non-linear least square method. The GAB model was found the most satisfactory for representation of the equilibrium moisture content data for guar grain and guar gum splits. The equilibrium moisture content of guar gum splits was found to be significantly higher (p < 0.05) than that of guar grain. The isosteric heat of sorption was determined from the equilibrium moisture adsorption data using Clausius-Clapeyron type equation. Exponential relationship described well the dependence of isosteric heat of sorption on the equilibrium moisture content. The enthalpy-entropy compensation theory applied to sorption isotherms indicated enthalpy controlled sorption process.     

桃胶与阿拉伯胶性质的比较

桃胶与阿拉伯胶都可用于食品增稠剂,本文对其透明度、稳定性、表面张力、保持香气能力等方面与阿拉伯胶进行了比较,并对流变曲线进行了测定,对温度、pH和电解质对它们粘度的影响进行了研究和比较。从研究结果来看,桃胶与阿拉伯胶的流变性质相似,甚至有些性质方面,桃胶要明显优于阿拉伯胶。     

Dilute solution properties of wild sage (Salvia macrosiphon) seed gum

In this paper, the effect of salt type (sodium and calcium chlorides), salt concentration (0, 0.5, 20 and 50 mM) and temperature (20, 30 and 40 °C) on the properties of dilute sage seed gum (SSG) solutions were investigated. SSG was evaluated for intrinsic viscosity by various models i.e. Huggins, Kraemer, Higiro and Tanglertpaibul and Rao equations. The results showed that the Tanglertpaibul & Rao and Higiro equations were chosen as the best models for intrinsic viscosity determination of SSG at different temperatures and salts concentrations, respectively. The increase in ionic strength of the NaCl and CaCl₂ from 0 to 0.5 mM caused increase in intrinsic viscosity, but increasing the temperature from 20 to 40 °C and salts concentrations from 0.5 to 50 mM decreased the intrinsic viscosity. Divalent ions from CaCl₂ showed a more pronounced effect on the intrinsic viscosity compared with monovalent ions from NaCl. SSG solutions at all temperatures and salts concentrations were in the dilute domain. The weight-average molecular weight of sage seed gum was obtained as 1.5 × 10⁶ Da.     

魔芋胶与其它重要植物胶功能性质的比较

本文介绍了植物胶的种类和分类,魔芋胶的结构和功能特性及魔芋胶与其他主要植物胶之间的结构、功能特性和在食品工业中的应用等方面的比较。以便使食品研发人员能够更加清楚地了解包括魔芋胶在内的主要植物胶的应用范围和功能特性。     

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     

Rheological behavior and stability of d-limonene emulsions made by a novel hydrocolloid (Angum gum) compared with Arabic gum

Our goal was to evaluate emulsion stability, droplet size analysis and rheological behavior of the emulsions prepared by a native biopolymer namely Angum gum (An) compared with Arabic gum (Ar) stabilized emulsions. After gum extraction, gum dispersions with maltodextrin were prepared in water (in 1-5% concentrations) and emulsified with 5% and 10% d-limonene using high pressure homogenization. Statistical analysis revealed a significant influence of gum type and gum concentration on emulsion stability at α = 0.05. Flavor level was not important statistically in emulsion stability but it was the only factor with a significant influence (P < 0.05) on surface tension of the emulsions. The results showed that Angum gum was superior to Arabic gum in stabilizing emulsions during storage. Also, rheological data revealed that Angum gum-emulsions’ behavior was following the Herschel-Bulkley model with higher viscosities compared to Arabic gum emulsions, which could be the main reason of higher emulsion stabilities with this novel hydrocolloid.