Rhamsan Gum Research Articles

Cricket Protein as an Innovative Emulsifier for Avocado Oil: Formulation and Characterization of Sustainable Emulsions

The use of cricket protein in emulsions is in line with the growing interest in sustainable food sources, as crickets require minimal resources and produce lower greenhouse gas emissions than traditional livestock. Research in this area suggests that incorporating cricket protein into emulsions not only improves their nutritional value but also contributes to the development of environmentally friendly and functional food products. This study proposes the use of cricket protein for the stabilization of emulsions formulated with avocado oil as a dispersed phase. This oil is rich in monounsaturated fats, particularly oleic acid, and a variety of bioactive compounds. In the first part of this study, we assessed the influence of the emulsifier concentration and found that 2 wt.% is the optimum because a depletion flocculation effect was produced. Subsequently, processing was optimized using ultrasonication so that the higher energy input produced emulsions with a droplet diameter of less than 700 nm. Finally, rhamsan gum was added to the formulation, producing emulgels with improved pseudoplastic behavior and physical stability. This study demonstrates that cricket protein in combination with rhamsan gum is capable of forming stable, low-droplet-size emulgels with potential applications in encapsulation systems.

Influence of the Homogenization Pressure on the Rheology of Biopolymer-Stabilized Emulsions Formulated with Thyme Oil

Different continuous phases formulated with ecofriendly ingredients such as AMIDET® N, an ecological surfactant, as well as welan and rhamsan gums were developed. An experimental design strategy was been in order to study the influence of the ratio of these two polysaccharides and the homogenization pressure applied in a microfluidizer on the critical shear stress for the continuous phases developed. A pure rhamsan gum solution was selected as the starting point for further study based on the production of thyme oil-in-water emulsions. The effect of the homogenization pressure on the physical stability, critical shear stress and droplet size distribution was analyzed for emulsions with optimized values of the rhamsan–welan ratio. These bioactive thyme oil-in-water emulgels could be considered as delivery systems with potential applications in the food industry.

Development of emulgels formulated with sweet fennel oil and rhamsan gum, a biological macromolecule produced by Sphingomonas.

In this work, a current application of rhamsan gum, a biological macromolecule which belongs to the sphingans group, as an efficient stabilizer of emulsions and emulgels is investigated. The main objective of this investigation was 1) to study the influence of glycerol and sweet fennel oil concentration on microfluidized emulsion properties; and 2) to develop stable emulgels stabilized with rhamsan gum. The emulsions and emulgels were characterized by droplet size, rheological properties, physical stability and microstructure. An analysis by surface response methodology of the results obtained revealed that essential oil concentration was the most determining factor affecting emulsion mean droplet sizes and rheological properties. An optimal emulsion with minimum d4,3 was obtained for the sample formulated with 10 wt% sweet fennel oil and 0 wt% glycerol. However, all of these emulsions suffered destabilization by creaming. The results of the rheological characterization of emulsions formulated with the biological macromolecule showed that the addition of 0.2 wt% of rhamsan gum allows an emulgel with enhanced physical stability to be obtained. Thus, we provide valuable information concerning the use of rhamsan gum as emulsion stabilizer and the development of stable emulsions and emulgels for use in the food industry.

A Comparison of the Effect of Temperature on the Rheological Properties of Diutan and Rhamsan Gum Aqueous Solutions

The rheological properties exhibited by gums make its use in applications interesting, such as foods, cosmetics, enhanced oil recovery, or constructions materials. Regardless of application field, the effect of temperature on these properties is of great importance, since these properties can be modified and cause the gum not to be useful for those conditions. Diutan and rhamsan gums are biopolymers, belonging to the sphingans, with similar structures which differ in the substituents of their side chains. It is known that both gums exhibit suitable viscoelastic properties and flow behavior when used as a stabilizer, gelling agent, or thickener. Both gums are widely used in food industry, personal care products, construction materials, oil operations, etc. For this reason, to know the effect of the temperature on their rheological properties is very helpful. For this purpose, small amplitude oscillatory shear measurements and flow curves, as a function of the temperature from 10 °C to 60 °C, have been performed, and the results obtained for both gums compared. The obtained results provide interesting information from an industrial point of view, since they reveal that the rheological properties remained almost unaltered in the temperature range assessed with diutan gum aqueous solutions, being slightly more viscous and viscoelastic than rhamsan gum solutions.

Rheological behavior of aqueous dispersions containing blends of rhamsan and welan polysaccharides with an eco-friendly surfactant

Small amplitude oscillatory shear and steady shear flow properties of rhamsan gum and welan gum dispersions containing an eco-friendly surfactant (a polyoxyethylene glycerol ester) formulated to mimic the continuous phase of O/W emulsions were studied using the surface response methodology. A second order polynomial equation fitted the influence of surfactant concentration, rhamsan/welan mass ratio and total concentration of polysaccharides. Systems containing blends of rhamsan and welan did not show synergism but thermodynamic incompatibility and made it possible to adjust the linear viscoelastic and low shear rate flow properties to achieve values in between those of systems containing either rhamsan or welan as the only polysaccharide.All the systems studied exhibited weak gel rheological properties as the mechanical spectra displayed the plateau or rubber-like relaxation zone, the linear viscoelastic range was rather narrow and flow curves presented shear thinning behavior, which fitted the power-law equation. While mechanical spectra of the systems studied demonstrated that they did not control the linear viscoelastic properties of the corresponding emulsions, the blend of rhamsan and welan gums was able to control the steady shear flow properties.

Statistical experimental design optimization of rhamsan gum production by Sphingomonas sp. CGMCC 6833.

Rhamsan gum is a type of water-soluble exopolysaccharide produced by species of Sphingomonas bacteria. The optimal fermentation medium for rhamsan gum production by Sphingomonas sp. CGMCC 6833 was explored definition. Single-factor experiments indicate that glucose, soybean meal, K(2)HPO(4) and MnSO(4) compose the optimal medium along with and initial pH 7.5. To discover ideal cultural conditions for rhamsan gum production in a shake flask culture, response surface methodology was employed, from which the following optimal ratio was derived: 5.38 g/L soybean meal, 5.71 g/L K(2)HPO(4) and 0.32 g/L MnSO(4). Under ideal fermentation rhamsan gum yield reached 19.58 g/L ± 1.23 g/L, 42.09% higher than that of the initial medium (13.78 g/L ± 1.38 g/L). Optimizing the fermentation medium results in enhanced rhamsan gum production.

Rhamsan gum production by Sphingomonas sp. CGMCC 6833 using a two‐stage agitation speed control strategy

Varying the agitation speed could greatly affect rhamsan gum production by Sphingomonas sp. CGMCC 6833. Batch fermentations at agitation speeds of 400, 600, 800, and 1,000rpm were therefore carried out. The time course of specific cell growth rate, specific glucose consumption rate, and specific rhamsan gum formation rate was subsequently determined. Based on the results, a novel two-stage agitation speed control strategy was developed. From 0 to 13H, the high specific cell growth and glucose consumption rates were achieved by setting the agitation speed of the fermenter at 800rpm. From 13H onward to the end of fermentation, the glucose consumption rate and specific cell growth rate were high at the agitation speed of 600rpm. Using this method, the maximum concentration and productivity of rhamsan gum reached 21.63±1.76gL(-1) and 0.338±0.028gL(-1) H(-1) , respectively, which were both higher than the optimum results obtained at constant agitation speeds.

The Principles of Starch Gelatinization and Retrogradation

The polysaccharides, such as κ-carrageenan, ι-carrageenan, agarose (agar), gellan gum, amylose, curdlan, alginate, and deacetylated rhamsan gum, in water changed into an ice-like structure with hydrogen bonding between polymer and water molecules, and between water-water molecules even at a concentration range of 0.1% - 1.0% (W/V) at room temperature, resulting in gelation. Such dramatic changes from liquid into gels have been understood at the molecular level in principles. In this review, we describe the structure-function relationship of starch on the view point of rheological aspects and discuss gelatinization and retrogradation mechanism including water molecules at molecular level. The starch molecules (amylose and amylopectin) play a dominant role in the center of the tetrahedral cavities occupied by water molecules, and the arrangement is partially similar to a tetrahedral structure in a gelatinization process. The arrangement should lead to a cooperative effect stabilizing extended regions of ice-like water with hydrogen bonding on the surface of the polymer molecules, where hemiacetal oxygen and hydroxyl groups might participate in hydrogen bonding with water molecules. Thus, a more extended ice-like hydrogen bonding within water molecules might be achieved in a retrogradation process. Though many investigations not only include starch gelatinization and retrogradaion, but also the gelling properties of the polysaccharides have been undertaken to elucidate the structure-function relationship, no other researchers have established mechanism at the molecular level. There is reasonable consistency in our investigations.

Production of Rhamsan Gum Using a Two-Stage pH Control Strategy by Sphingomonas sp. CGMCC 6833

In this paper, the production of rhamsan gum from Sphingomonas sp. CGMCC 6833 at different pH values was investigated. Based on kinetic analysis, a two-stage strategy for pH control was proposed. During the first 10 h, pH was controlled at 7.5 to maintain high specific cell growth rate and specific glucose consumption rate. After 10 h, pH decreased naturally to 7.0; this value was retained to maintain high specific rhamsan gum formation rate. Using this method, the maximum concentration and productivity of rhamsan gum reached 18.56 ± 1.68 g/L and 0.290 ± 0.026 g/L/h, which are 12.83 and 12.84 % higher than the optimum results obtained at natural pH, respectively.

Ninety-day oral toxicity study of rhamsan gum, a natural food thickener produced from Sphingomonas ATCC 31961, in Crl:CD(SD)IGS rats

This study was designed to evaluate and characterize any subchronic toxicity of rhamsan gum, a polysaccharide produced from Sphingomonas strain ATCC 31961, when administered to both sexes of Crl:CD(SD)IGS rats at dietary levels of 0 (control), 0.5, 1.5, and 5.0% (10 rats/sex/group). During the study, the treatment had no adverse effects on clinical signs, survival, body weights and food and water consumption, or on findings of urinalysis, ophthalmology, hematology, or blood biochemistry. Examination of gross pathology and histopathology exhibited no differences of toxicological significance between control and treated rats. Increased relative cecum (filled) and cecum (empty) weights, evident in males of 1.5% group and both sexes of the 5.0% group, were considered to be a physiological adaptation. Thus, the results indicated the toxic level of rhamsan gum to be more than 5.0%, and the no-observed-adverse-effect level (NOAEL) was concluded to be 5.0% (3,362 mg/kg body weights/day for males, and 4,304 mg/kg body weights/day for males) from the present study.

Gelation mechanism of deacetylated rhamsan gum

Non-Newtonian behaviour and dynamic viscoelasticity of deacetylated rhamsan gum in aqueous solution were measured with a rheogoniometer. The flow curves, at 25 °C, of deacetylated rhamsan gum showed Newtonian behaviour at concentrations below 0.2%, but plastic behaviour above 0.3%. The yield value of the last named solutions was estimated to be 8.0 and 11.0 Pa at 0.3 and 0.5%, respectively. The elastic modulus increased with an increase in concentration and gelation occurred at a concentration above 0.3%. The elastic modulus for a solution of 0.3% decreased a little with increase in temperature up to 30 °C, then it showed a constant value with increase in temperature. However, when the temperature reached 50 °C, which was estimated to be a transition temperature, the elastic modulus decreased rapidly with further increase in temperature. The elastic modulus of the deacetylated rhamsan (0.2%) increased with addition of CaCl 2 (6.8 mM) and gelation occurred at low temperature (0 °C). The elastic modulus showed a little high value in the presence of urea (4.0 M). Possible gelation mechanism of the deacetylated rhamsan was proposed.

Study of Pipeline Transportation of Dense Fly Ash-Water Slurry

This paper proposes a long distance pipeline transportation system with an additive feeding system suitable for restarting after more than a 24-hour shut down. The aim of the investigation is to find suitable stabilizing additives for fly ash-water slurry to prevent sedimentation during an interrupted period of pipelining. Rheological characteristics and sedimentation stability of the slurry with the addition of four kinds of stabilizing additives were measured. Additives used in this study were rhamsan gums, carboxymethyl cellulose, and xanthan gum. The stable slurry was fed in the pipeline, instead of the normal slurry, before the pipeline was shut down. From the predicted viscosity, using Usui's thixotropy model, the relationship between flow rate and pressure drop has been estimated for the transportation of the slurry. A feasibility study for the new transport system was also performed.

97/00160 Rheological properties and some applications for rhamsan and xanthan gum solutions

97/00160 Rheological properties and some applications for rhamsan and xanthan gum solutions

Rheological Properties and Some Applications for Rhamsan and Xanthan Gum Solutions

The rheological properties of solutions of xanthan gum (Kelzan® D) and three rhamsan gums, S-60, S-130 and S-194, are examined. Effects studied include those of temperature, concentration and (for the rhamsan gums) extent of side chain branching. Solutions of greater viscosity and elasticity at most shear rates result as the degree of branching increases. When compared with xanthan gum, S-194 is found to be less temperature sensitive and more stable to excess shear. The use of these polymers in two commercial applications, i.e. coal–water mixtures and timber preservative emulsions, is also examined. Several advantages are identified when rhamsan gums are used instead of xanthan gum in both cases.

Polysaccharide lyases from gellan-producing Sphingomonas spp.

A number of Sphingomonas strains capable of synthesizing the bacterial exopolysaccharide gellan and related polymers were shown to possess constitutive gellanase activity. In each case, the degradation of deacylated gellan was due to extracellular, eliminase-type enzymes (lyases) which cleave the sequence ... beta-D-glucosyl 1,4-beta-D-glucuronosyl ... in the tetrasaccharide repeat unit of the substrate polysaccharides. Deacetylated rhamsan was an alternative substrate but there was little or no action against most other polysaccharides with similar structures. Slight differences were found between the specificities of the lyases from different strains. Activities of gellan lyase preparations were generally low. As well as the extracellular 'gellanase' activity, all the bacteria possessed varying amounts of beta-D-glucosidase and beta-D-glucuronidase activities apparently located in the periplasm. The products from deacylated gellan and the chemically deacylated form of polysaccharide S194 (rhamsan gum), which is effectively a gentiobiosylated form of gellan, closely resembled those recently obtained by the authors from other, gellan-degrading, non-gellan-producing bacteria. The enzymes had negligible activity against the natural, acylated gellan and rhamsan polysaccharides from bacteria now designated as strains of Sphingomonas.

F255. Rheological effects of adding organic solvents to rhamsan gum solutions

F255. Rheological effects of adding organic solvents to rhamsan gum solutions

Gellan lyases-novel polysaccharide lyases

A number of bacterial strains capable of degrading the bacterial exopolysaccharide gellan have been isolated by standard enrichment procedures. They include several pink-pigmented Gram-negative rod-shaped bacteria. A red-pigmented Gram-positive bacillus earlier found to degrade the exopolysaccharide xanthan from Xanthomonas campestris also showed slight gellanase activity. All the Gram-negative bacteria are non-fermentative, motile and amylase-producing. The gellan degradation in each case is due to eliminase-type enzymes (lyases) which appear to be extracellular enzymes cleaving the sequence... beta-D-glucosyl-(1-->4)-beta-D-glucuronosyl... in the tetrasaccharide repeat unit of the substrate polysaccharides. Although in some isolates these enzymes appear to be exo-acting, it appears from the loss in viscosity of the alternative substrate deacetylated rhamsan that they are predominantly endoenzymes. The enzyme activity is inducible: it is almost absent from glucose-grown cells. Associated with the 'gellanase' activity, all the Gram-negative bacterial isolates possess intracellular alpha-L-rhamnosidase and beta-D-glucosidase activities apparently located in the periplasm. The enzymes are highly specific and fail to cause significant degradation of most of the other bacterial exopolysaccharides which have been shown to be structurally related to gellan. As well as acting on gellan, they exert similar degradative activity against the chemically deacylated form of polysaccharide S194 (rhamsan gum), which is effectively a gentiobiosylated form of gellan. The enzymes only have relatively slight activity against the natural, acylated gellan-like polysaccharides from the bacteria now designated as strains of Sphingomonas paucimobilis.

Molecular origin of thermal stability of rhamsan gum in aqueous media.

Journal Article Molecular Origin of Thermal Stability of Rhamsan Gum in Aqueous Media Get access Masakuni Tako Masakuni Tako Department of Bioscience and Biotechnology, University of the Ryukyus, Nishihara, Okinawa 903–01, Japan Search for other works by this author on: Oxford Academic Google Scholar Bioscience, Biotechnology, and Biochemistry, Volume 57, Issue 7, 1 January 1993, Pages 1182–1184, https://doi.org/10.1271/bbb.57.1182 Published: 01 January 1993 Article history Received: 09 September 1992 Published: 01 January 1993