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Xanthan Gum (xanthan + gum)

Distribution by Scientific Domains

Chemistry	73%
Life Sciences	13%

Distribution within Chemistry

General & Introductory Food Science & Technology	82%
Chemical Engineering	10%

Selected Abstracts

RHEOLOGICAL AND PHYSICAL PROPERTIES OF DATE JUICE PALM BY-PRODUCT (PHOENIX DACTYLIFERA L.) AND COMMERCIAL XANTHAN GUMS

JOURNAL OF TEXTURE STUDIES, Issue 2 2010
RIADH BEN SALAH
ABSTRACT Rheological and thermal properties of xanthan produced by Xanthomonas campestris from date by-products (DBP-xanthan) and commercial xanthan were determined. DBP-xanthan gave solutions with lower apparent viscosity than commercial xanthan. However, DBP-xanthan solutions were more stable to temperature changes and ionic strength than commercial xanthan. Gradual increase of storage modulus (G,) as function of frequency was observed for the two polysaccharides. On the other hand, loss modulus (G,) remained constant for DBP-xanthan and an increase was observed for commercial xanthan. Granulometric profile indicates that DPB-xanthan particle size was lower than commercial xanthan. Differential scanning calorimetry showed that the melting temperatures (Tm) and enthalpy (,Hm) of DBP-xanthan were higher than those of commercial xanthan. These properties of DBP-xanthan are quite rare among xanthan described in the literature and give this new gum great potential for use in the field of bioindustries as thickening and stabilizing agents. PRACTICAL APPLICATIONS Xanthan gum from date by-products (DBP-xanthan) was recently produced in our laboratory. No work has been undertaken to study the rheological properties of this polysaccharide to date. Rheological and some physicals properties were compared to those of commercial xanthan. This could promote industrial use of DBPs as low-cost natural source for xanthan gum production. [source]

An investigation of some food-approved polymers as agents to inhibit hydroxyapatite dissolution

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2005
Michele E. Barbour
Dental erosion involves dissolution of the hydroxyapatite fraction of enamel and dentine, so agents that reduce the dissolution rate of hydroxyapatite could find application in food products aimed at reducing erosion. This study was performed to test some common food ingredients and additives for their effect on the dissolution rate of hydroxyapatite in a citric acid solution representative of soft drinks. Pyrophosphate, tripolyphosphate and a linear chain polyphosphate (average 25 phosphate units) significantly reduced the hydroxyapatite dissolution rate by 35, 46 and 64%, respectively. Xanthan gum and carboxymethylcellulose significantly reduced the hydroxyapatite dissolution rate by 29 and 16%, respectively. The protective effect may be ascribed to the binding of condensed phosphate or to the formation of an adsorbed layer of gum at the hydroxyapatite surface. Several other common food additives had no statistically significant effect on the hydroxyapatite dissolution rate. Polyphosphate exhibited a considerable persistence of action, causing a reduction in the dissolution rate for 3 h after treatment. Tripolyphosphate was slightly persistent, and pyrophosphate and xanthan gum did not exhibit a substantial persistence of action. A solution containing polyphosphate and xanthan gum reduced the hydroxyapatite dissolution rate by 70% and exhibited a similar persistence of action to the solution containing only polyphosphate. These compounds are suggested to have potential as erosion-reducing agents in soft drinks. [source]

RHEOLOGICAL AND PHYSICAL PROPERTIES OF DATE JUICE PALM BY-PRODUCT (PHOENIX DACTYLIFERA L.) AND COMMERCIAL XANTHAN GUMS

Development of low-fat mayonnaise containing polysaccharide gums as functional ingredients

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2010
Hou-Pin Su
Abstract BACKGROUND: The objective of this study was to develop a low-fat (LF) mayonnaise containing polysaccharide gums as functional ingredients. Xanthan gum (XG, 15 g kg,1), citrus fiber (CF, 100 g kg,1) and variable concentration of guar gum (GG) were used to formulate the optimum ratios of polysaccharide gums as fat replacers. The fat content in LF mayonnaise was reduced to 50% if compared with full-fat (FF) mayonnaise, and the products still maintained ideal rheological properties. RESULTS: The rheological parameters showed that there were no (P > 0.05) differences in yield stress, viscosity and flow behavior index between XG + 10 g kg,1 GG, CF + 5 g kg,1 GG and FF control. LF mayonnaises had lower caloric values and higher dietary fiber content than the FF counterpart. Scanning electron microscopy (SEM) micrographs illustrated that the network of aggregated droplets in LF treatments contained a large number of interspaced voids of varying dimensions. Furthermore, in a comparison of sensory evaluation of LF treatments with commercial and our FF mayonnaises, there were no (P > 0.05) differences in any sensory scores among XG + 10 g kg,1 GG control. CONCLUSION: This study shows that XG + 10 g kg,1 GG and CF + 5 g kg,1 GG could be used in LF mayonnaise formulations based on its multiple functions on processing properties. Copyright © 2010 Society of Chemical Industry [source]

Effect of medium molecular weight xanthan gum in rheology and stability of oil-in-water emulsion stabilized with legume proteins

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2005
Evdoxia M Papalamprou
Abstract Xanthan gum is a water-soluble extracellular polysaccharide that has gained widespread commercial use because of its strong pseudoplasticity and tolerance to high ionic strength, which bring unique rheological properties to solutions. This study compares and evaluates the emulsifying properties of oil-in-water (30:70 v/v) emulsions stabilized with lupin and soya protein isolates and medium molecular weight xanthan gum. The protein was obtained by an isoelectric precipitation method and the polysaccharide was produced by Xanthomonas campestris ATCC 1395 in batch culture in a laboratory fermenter (LBG medium) without pH control. The addition of xanthan gum in the emulsion formulation enhances emulsion stability through the phenomenon of thermodynamic incompatibility with the legume protein, resulting in an increase of the adsorbed protein at the interface. The emulsion stability is also enhanced by a network structure built by the polysaccharide in the bulk phase. Copyright © 2005 Society of Chemical Industry [source]

Development of emulsion from rhizobial fermented starch industry wastewater for application as Medicago sativa seed coat

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2010
Rojan Pappy John
Abstract Starch industry wastewater was efficiently employed for the production of Sinorhizobium meliloti and the concentrated culture was used for the development of a biofertilizer formulation. Tween-80 (0.02,g/L) acted as the best emulsifier for a Sinorhizobium,canola oil emulsion. The stability of the emulsion and survival of the organism was enhanced by supplementation of xanthan gum at pH 8. The refrigerated condition was most favorable for stability and survival of the microorganism. The survival of microorganism at 4±1°C was 2.78×1010 and 2.01×1010,CFU (colony forming unit)/mL on storage for 1 and 2 months, respectively. The values were higher than the prescribed cell count (×103,CFU/mL) for field application. At 40°C, the survival of bacteria reduced from 3×1010,CFU/mL to 8.1×109 and 8.8×106,CFU/mL in 1 and 2 months, respectively. Emulsion-coated seed was incubated at different temperatures and a cell count of 105,CFU/seed was observed after 2 months of storage at 4°C, which was equal to the highest level of the described requirement (103,105,CFU/seed). Emulsion supplemented with xanthan gum improved the shelf-life under optimized conditions (Sinorhizobium concentrate,,,canola oil (1:1) emulsion with 0.02,g/L Tween-80; storage at pH 8 and temperature 4±1°C) and this emulsion with the required cell count and prolonged viability was used for the pre-inoculation of seed or for in situ soil application. [source]

An investigation of some food-approved polymers as agents to inhibit hydroxyapatite dissolution

Bionanocomposites as New Carriers for Influenza Vaccines

ADVANCED MATERIALS, Issue 41 2009
Eduardo Ruiz-Hitzky
Bionanocomposites resulting from the assembly of negatively charged polysaccharides (xanthan gum) and sepiolite at the nanometer scale are able to associate efficiently to influenza-virus particles. This produces stable dispersions suitable as effective intranasal or intramuscular flu vaccines, as confirmed from experiments carried out in mice. [source]

EFFECTS OF APPLICATION PARAMETERS AND ADJUVANTS ON THE FOLIAR SURVIVAL AND PERSISTENCE OF ENTOMOPATHOGENIC NEMATODE STEINERNEMA CARPOCAPSAE ALL STRAIN ON CABBAGES

INSECT SCIENCE, Issue 2 2004
Yong-ling Jin
Abstract, Effects of the critical parameters (spray pressure, the distance between a sprayer and the sprayed plant, the concentration of infective juveniles (Us), volumes of the sprayed suspension of IJs, the temperature and humidity combinations) and the addition of various adjuvants on the survival and persistence of entomopathogenic nematode Steinernema carpocapsae All strain on leaf surfaces of the Chinese cabbage Brassica pekingensis were determined. The results showed that (1) The pressure of a sprayer had negative influence on the persistence of IJs on the leaf. (2) The numbers of the living IJs collected on the leaf significantly increased with the IJ dosages applied on the leaf when the dosage was over 2 000 IJs per mL. (3) More IJs (from 10.1 IJs/cm2 to 45.5 IJs/cm2) were collected on the leaf when more volumes of IJ suspension (from 3.3 mL to 19.8 mL) were sprayed. However, when the highest volume of IJ suspension was used, the IJ numbers collected did not increase. (4) In general, the survival of the IJs on the leaf decreased with the exposure time. (5) The formulation of IJs by adding xanthan gum, a sticker and detergent surfactant enhanced the survival and persistence of IJs. The number of living IJs on the leaf with 0.3 % of xanthan gum was 150 times higher than that of the IJs with water alone. IJ suspensions with different concentrations of glycerin and with 0.5 % molasses and 0.01 % detergent surfactant showed similar effects. [source]

The effect of long-term frozen storage on the quality of frozen and thawed mashed potatoes with added cryoprotectant mixtures

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2009
Cristina Fernández
Summary Cryoprotectant mixtures were added to frozen/thawed (F/T) mashed potatoes in the form of amidated low-methoxyl (ALM) pectin and xanthan gum (XG), kappa-carrageenan (,-C) and XG and sodium caseinate (SC) and XG, and the effect of frozen storage was examined. F/T mashed potatoes without added biopolymers had higher storage modulus G, after freezing and frozen storage, associated with sponge formation due to amylose retrogradation. Oscillatory measurements indicated weakening of the structure of mashed potatoes without biopolymers and with added ,-C/XG and SC/XG mixtures at the end of storage due to ice recrystallisation, whereas the structure of samples with added ALM/XG mixtures was reinforced by increasing time in storage. Mashed potatoes with added mixtures exhibited water-holding capacity for 1 year. Samples with added ,-C/XG mixtures were more structured, although when both ,-C/XG and SC/XG mixtures were included in mashed potato, very acceptable sensory quality was maintained in usual frozen storage conditions. [source]

Quality changes in frozen and thawed, cooked puréed vegetables containing hydrocolloids, gums and dairy powders

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2002
Gerard Downey
Summary Freezing and thawing have been shown to adversely affect the centrifugal drip loss and maximum resistance to penetration of cooked, puréed vegetables (potatoes, carrots and turnips). Amelioration of these effects has been investigated through the addition of cryoprotectants (xanthan gum, guar gum, pectin, carrageenan, sodium caseinate, whey protein concentrate). The effect of each cryoprotectant varied with vegetable type. In general, gums (xanthan and guar) proved most effective in reducing drip losses although carrageenan and pectin exhibited some ability in this regard. Dairy powders produced no effect on drip loss but did alter maximum resistance values after thawing. Depending on the vegetable, quality maintenance or improvement after thawing may be achieved through selection of an appropriate cryoprotectant. [source]

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

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2009
PATRICK D. WILLIAMS
ABSTRACT 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. [source]

MODEL PREDICTION FOR SENSORY ATTRIBUTES OF NONGLUTEN PASTA

JOURNAL OF FOOD QUALITY, Issue 6 2001
JEN-CHIEH HUANG
ABSTRACT 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. [source]

Adsorption and rheological properties of biopolymers at the air-water interface

AICHE JOURNAL, Issue 7 2006
Rosa Baeza
Abstract Dynamics of adsorption and viscoelasticity of biopolymers (,-lactoglobulin (,-lg) + polysaccharides (PS)) at 20 °C and pH 7 have been studied. Protein concentration in the bulk phase was 0.1 wt %, and the concentration of polysaccharides (xanthan gum, ,-carrageenan, and propylenglicol alginate with different degrees of esterification and viscosity) was varied from 0.1% to 0.5 wt %. The results reveal a significant effect of surface-active and non surface-active polysaccharides on the dynamics of the formation and viscoelasticity of adsorbed films at the air-water interface. The rate of diffusion of the biopolymers increased in the mixed systems, but the effect was more significant at the highest concentration of polysaccharide (0.5 wt %). The rate of rearrangement of the adsorbed films decreased in the presence of polysaccharides as compared to the protein film. Competitive adsorption, complexation and limited thermodynamic incompatibility between ,-lactoglobulin and polysaccharide would explain the observed effects. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source]

MODELING OF TEXTURE EVOLUTION OF CAKES DURING STORAGE

JOURNAL OF TEXTURE STUDIES, Issue 1 2010
MANUEL GÓMEZ
ABSTRACT The aim of this work is to model the variation of texture parameters in cakes during staling. The evolution was studied in layer cakes (cake A) and sponge cakes (cake B). The effect of storage temperature and the addition of fiber, xanthan gum (cake A) and emulsifier (cake B) were also studied. The best model to adjust the texture parameters variation during storage in both kinds of cakes was square root x (y = a + b * x1/2), except for firmness and springiness in cakes B. Firmness and springiness were adjusted the best to the linear model. In the model, y stood for the textural parameters and x for the time. a and b were related to the initial value of the studied parameter and with its change over time respectively. In both kinds of cakes, A and B, the firmness and gumminess increased, and the cohesiveness, springiness and resilience decreased, as the storage time increased. The increase in the storage temperature and the addition of fiber minimized the firmness changes in both kinds of cakes. PRACTICAL APPLICATIONS This methodology simplifies the study of cake textural parameters during storage and the result interpretation. Moreover, the correlation analysis has demonstrated that the number of textural parameters of cakes to study can be reduced. [source]

A COMPARATIVE STUDY OF THE PERFORMANCE OF SELECTED IN-LINE VISCOMETERS ON NEWTONIAN AND SHEAR-THINNING FLUIDS,

JOURNAL OF TEXTURE STUDIES, Issue 2 2001
LAURA A. ZIMMER
Three commercial instruments for in-line process measurement of fluid viscosity (an oscillating sphere viscometer, a tube viscometer and a coaxial cylinder viscometer) were evaluated using a Newtonian (60% sucrose) and two shear-thinning fluids (0.5% xanthan gum and 2% hydroxypropyl methylcellu-lose). The oscillating sphere viscometer required little or no calibration to measure the viscosity of Newtonian fluids. Otherwise, when compared to results given by analytical off-line rheometry, the in-line viscometers were found to be grossly inaccurate in predicting viscosity. A methodology is presented to correct the flow curves generated by each in-line instrument such that the output measurements are consistent with that given by off-line rheometry. Additional characteristics of each instrument that should be considered when choosing an instrument for in-line process application are presented. [source]

Textural properties of legume protein isolate and polysaccharide gels

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2006
Eleousa A Makri
Abstract The influence of legume proteins from lupin, pea and fababean on the formation of gels prepared by heat treatment in the absence or presence of xanthan gum, locust bean gum and NaCl was investigated. The resulting fracture and texture properties of gels not only are associated with the heating process used to form the gel but also depend on the conformational aspects of xanthan,locust bean gum in admixture with legume proteins, which after 10 days of aging reinforce the system. The fracture and textural properties are explained in terms of the effect of the protein,polysaccharide molecular structure and physicochemical conditions applied in the gel system during the gel preparation and measurements. Copyright © 2006 Society of Chemical Industry [source]

Effect of medium molecular weight xanthan gum in rheology and stability of oil-in-water emulsion stabilized with legume proteins

Pyrolysis mass spectrometry for distinguishing potential hoax materials from bioterror agents,

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2006
Jon G. Wilkes
Pyrolysis mass spectrometry (PyMS) was investigated as a rapid tool to distinguish potential bioterror hoax materials from samples containing pathogenic bacteria. A pyrolysis time-of-flight (TOF) mass spectrometer equipped with an alternative ionization technique, metastable atom bombardment (MAB), was used to produce sample spectra. These spectra were analyzed by principal component and discriminant analysis for pattern recognition. Materials investigated were two strains of Vibrio parahaemolyticus, one of which produced the tdh toxin, two Salmonella enterica serotypes, a biological mosquito control product containing spores of Bacillus thuringiensis, and several white to off-white powders (which could be used as hoax materials), such as flour, corn starch, methyl cellulose, and xanthan gum. PyMS distinguished bacterial samples from hoax materials. Furthermore, pattern analysis differentiated Vibrios from Salmonellae, Salmonella enterica Anatum from S. enterica Heidelberg, and the two V. parahaemolyticus strains from each other. The B. thuringiensis mixture was distinguished from other bacteria and powders, suggesting that PyMS with pattern recognition may differentiate samples containing pathogens, including Bacillus spp., from nonbiological agents and that it can be a rapid method for detection of bacteria. MS data acquisition took only 7 min for each sample. Published in 2006 by John Wiley & Sons, Ltd. [source]

Interaction between aqueous solutions of polymer and surfactant and its effect on physicochemical properties

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2008
Mohammad Yunus Khan
Abstract Interaction between water-soluble polymers and anionic surfactants has been studied by surface tension and conductivity measurements. Sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS) were used as surfactant while polyacrylamide (PAA), commercial grade partially hydrolyzed polyacrylamide (PHPA), and xanthan gum were used as water-soluble polymers for the present study. The behavior of surfactant,polymer interaction was found to be dependent on both surfactant and polymer concentrations. After the critical aggregation concentration (CAC), interaction between the water-soluble polymer and surfactants was started and above the polymer saturation point (PSP) polymer was saturated by surfactant with no further change of surface tension and conductivity of the solution. It has also been found that alkali (NaOH) and salts (Na2CO3, NaCl) have significant influence on the polymer,surfactant interaction. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

Mass Transfer in Blood Oxygenators Using Blood Analogue Fluids

BIOTECHNOLOGY PROGRESS, Issue 4 2002
S. Ranil Wickramasinghe
Mass transfer correlations for hollow fiber blood oxygenators have been determined experimentally using Newtonian and non-Newtonian blood analogue fluids. The Newtonian fluids consisted of deionized water and glycerol/water mixtures. The non-Newtonian fluids were prepared by adding small amounts of xanthan gum to the Newtonian blood analogue fluids. The rheological behavior of the non-Newtonian blood analogue fluids was modeled using the power law. The diffusion of oxygen into and out of the Newtonian and non-Newtonian blood analogue fluids has been studied. The liquid stream flowed outside and across bundles of woven hollow fibers, while the gas stream flowed inside the fibers. [source]