Fabrication of pickering high internal phase emulsions stabilized by pecan protein/xanthan gum for enhanced stability and bioaccessibility of quercetin

The stabilizing effect of pecan protein (PP)/xanthan gum (XG) complex on the Pickering high internal phase emulsion (HIPE) has been examined in this study. Shear viscosity of HIPEs increased with respect to XG concentration due to the formation of hydrogen bonds between PP and XG. Confocal laser scanning microscopy (CLSM) imaging showed fairly even distribution and polygonal shapes of oil droplets (30-70 μm). When used to encapsulate quercetin, this Pickering HIPE exhibited high retention rate and improved gel strength. Furthermore, the interface film of PP/XG on oil-water interface contributed to the high retention of quercetin in Pickering HIPEs when exposure to heat, iron ions, and hydrogen peroxide in aqueous phase. The bioaccessibility of quercetin after in vitro simulated digestion were also improved by HIPE encapsulation than that in oil. To conclude, PP/XG complex stabilized HIPEs may be suitable delivery systems for improving colloidal stability and bioaccessibility of hydrophobic bioactives.

Effect of oil on the performance of biopolymers as drag reducers in fresh water flow

This study looks at the effectiveness of natural polymers (biopolymers) as drag reducers in flows of oil-water mixtures. The technique of using drag reducers to minimize the frictional drag in pipeline transportation of fluids is getting more challenging and there is need to be more environmentally friendly by using natural polymers. In this report, two natural polymers: xanthan gum (XG) and guar gum (GG), were used as drag reducers in a 12-mm ID straight conduit with water. The concentration of the gums was varied from 50 to 250 pm while 25, 0.50 and 0.75 fractions of oil were mixed with freshwater. The molecular weight of the gums was also determined to gain insight into their influence on the rheology of the fluids. The result showed that the gums (natural polymers) performed better as drag reducer in freshwater than in mixture with oil. Specifically, the drag reduction (DR) of 200 pm GG and XG solutions at Reynolds number of 59000 in freshwater was 39% and 44% respectively, while with the addition of 50% oil fraction, it was reduced to 19% and 32% respectively. DR reduced with oil fraction. It was concluded that XG performs better in the presence of oil than GG.

Foaming process optimization, drying kinetics and quality of foam mat dried papaya pulp

This study was performed to optimize the papaya pulp foaming process and determine the effect of drying conditions on the drying kinetics and the quality of the obtained powder. Thus, the one- factor-at-a-time experimental method, followed by 2 ^k full factorial design was implemented to determine the optimal conditions of the foaming process. The factors studied were egg white percentage (EW%), xanthan gum percentage (XG%), and whipping time (WT) which varied between 5-20%, 0-0.5%, and 5-20 min, respectively. The optimum conditions (EW% of 15%, XG% of 0.3% and WT of 15 min) for papaya foam expansion percentage (FE%) resulted in a foam with the highest FE% (275.64%) and desirability of 0.916. Foamed and non-foamed papaya pulp in thickness layers of 2-, 4- and 6-mm were dried at 60° and 80° C. Foaming papaya pulp reduced drying time at various layer thicknesses from 140-400 min to 60-160 min, and from 70-160 min to 30-100 min at 60° and 80° C, respectively. Foamed powder samples had the lowest dissolution times and hygroscopicity values; in addition, reconstituted solutions were lighter than non-foamed solutions. Ascorbic acid retention and total phenolic compound content was adversely affected by increased drying time. The obtained papaya powder was classified into six groups based on its quality parameters via hierarchical cluster analysis. In general, foam mat drying is a promising method for producing papaya pulp powder due to its high drying rates and better-quality product.

Chitosan, xanthan and locust bean gum matrices crosslinked with β-cyclodextrin as green sorbents of aromatic compounds

Three different polysaccharides, xanthan gum, chitosan and locust bean gum, were crosslinked with or without β-cyclodextrin, using citric acid in different ratios, to create 'green' hydrogel matrices. The crosslinking of these polysaccharides was produced through an inexpensive and innocuous solvent-free synthesis process. A favorable swelling behavior of the hydrophilic matrices facilitates the sorption of the solutes tested. Interestingly, the amount of β-cyclodextrin groups is not the only factor to yield the best sorption capability for hydrophobic model molecules: polysaccharides themselves also influence the sorption depending on their characteristic functional groups, the conformation of their chains and, as mentioned above, their degrees of swelling. In order to ascertain the effect of the polysaccharides on the sorption capabilities of a model sorbate (1-naphthol), isotherms using a wide range of solute concentrations were analyzed, and the Hill equation yielded the best fitting results and provided some insight into the mechanisms of interaction.

Printability and bio-functionality of a shear thinning methacrylated xanthan - gelatin composite bioink

3D bioprinting is a recent technique that can create complex cell seeded scaffolds and therefore holds great promise to revolutionize the biomedical sector by combining materials and structures that more closely mimic the 3D cell environment in tissues. The most commonly used biomaterials for printing are hydrogels, however, many of the hydrogels used still present issues of printability, stability, or poor cell-material interactions. We propose that bio-inks with intrinsic self-assembling and shear thinning properties, such as xanthan gum, can be methacrylated (XGMA) and combined with a bio-functional material such as gelatin methacryloyl (GelMa) to create a stable, cell-interactive bio-ink with improved properties for 3D bioprinting. These biomaterials have reduced viscosity under high shear and recover their viscosity rapidly after the shear is removed, retaining their shape, which translates to easier extrusion whilst maintaining good fidelity after printing. This was confirmed in printing studies, with measured normalized strand widths of 1.2 obtained for high gel concentrations (5+5 % XGMA-GelMA). Furthermore, the introduction of a secondary photo-cross-linking method allowed tuning of the mechanical properties of the hydrogel with stiffness between 15 and 30 kPa, as well as improving the stability of the hydrogel with retention of 75 % of its mass after 90 days. The hydrogel was shown to be biocompatible and bio-active with 97 % cell viability, and cell spreading after 7 days of culture for low gel concentrations (3+3 % XGMA-GelMA). Shear stresses were relatively low while printing (1 kPa) as a result of the shear thinning property of the material, which supported cell viability during extrusion. Finally, printed hydrogels retained high cell viability for lower gel concentrations, and showed improved cell viability for more concentrated hydrogels when compared to cells cultured in bulk hydrogels, presumably due to improved nutrient/oxygen diffusion and cell migration. In conclusion, stability and formulation of a XGMA-GelMA shear thinning composite hydrogel has been optimized to create a bio-functional bio-ink, with improved printability, and in vitro culture stability via secondary photo-induced cross-linking, making this composite a promising bio-ink for 3D bioprinting.

Synthesis and application of eco-friendly superabsorbent composites based on xanthan gum and semi-coke

An eco-friendly superabsorbent composites of xanthan gum-g-polyacrylic acid/semi-coke (XG-g-PAA/SC) were fabricated via grafting of polyacrylic acid onto the XG in the presence of SC. The obtained products were characterized in combination with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The result indicated that the SC interacted with the polymeric network by hydrogen bond or electrostatic interaction. The swelling ratio of the best sample XG-g-PAA/SC (15 wt%) in distilled water and 0.9 wt% NaCl solution was 410.8 and 61.5 g/g by optimizing the polymerization conditions. In addition, compared with the blank sample (only containing soil), it can be found that adding a certain amount of XG-g-PAA/SC can significantly improve the soil water retention efficiency, which can be further proved by the results of plant pot experiment. Based on the above excellent swelling capacity, water holding capacity and plant growth promoting performance, it can be inferred that the XG-g-PAA/SC is expected to become a water retaining agent or soil regulator for plant growth.

Optimization xanthan gum, Roselle seed and egg white powders levels based on textural and sensory properties of gluten-free rice bread

A response surface methodology based on Box-Behnken design was deployed to optimize gluten-free bread formulation based on rice flour. Roselle seed powder (15, 25 and 35%), egg white powder (10, 20 and 30%) and xanthan gum (0.5, 0.75 and 1%) were selected as independent variables. The purpose of the optimization was to achieve maximum porosity and sensory properties as well as minimum hardness of bread samples. The results showed that the Roselle seed and egg white powders had a significant effect (p ≤ 0.05) on hardness, porosity and sensory characteristics of bread. However, xanthan gum did not show a significant effect (p > 0.05) on sensory properties. The design revealed the optimum formulation for gluten-free rice bread with low crumb firmness and improved porosity and sensory values by using 0.73, 30 and 25% of xanthan gum, Roselle seed and egg white powders, respectively. In addition, the optimized gluten-free bread showed higher nutritional properties in terms of total protein, ash, oil and fiber contents as well as lower staling rate compared to the control.

The degradation of xanthan gum in ionic and non-ionic denaturants studied by rheology and molecular dynamics simulation

The use of xanthan gum (XG) as a thickener increases solution viscosity, and therefore, the cost of subsequent processes such as fluid transportation and purification. Herein, we investigate the degradation of XG by urea, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB). The results showed that CTAB degraded the XG more than SDS or urea. Interestingly, the degree of CTAB-induced degradation varied with the concentration regime. Thus, increasing CTAB concentration from 0.01 to 0.1 M decreased the complex viscosity (|η*|), whereas from 0.2 to 0.5 M the |η*| increased. For XG/SDS, the |η*| was unchanged with increasing SDS concentration from 0.01 to 0.1 M, whereas it decreased from 0.2 to 0.5 M. For XG/urea, the |η*| was stable in all concentrations. At the atomic-scale, computer simulations revealed that the degrading effect of CTAB was due to preferential interaction with the XG sidechain. These findings can enhance industrial applications of XG.

Controlled treatment of a high velocity anisotropic aquifer model contaminated by hexachlorocyclohexanes

Xanthan gels were assessed to control the reductive dechlorination of hexachlorocyclohexanes (HCHs) and trichlorobenzenes (TCBs) in a strong permeability contrast and high velocity sedimentary aquifer. An alkaline degradation was selected because of the low cost of NaOH and Ca(OH)₂. The rheology of alkaline xanthan gels and their ability to deliver alkalinity homogeneously, while maintaining the latter, were studied. Whereas the xanthan gels behaved like non-Newtonian shear-thinning fluids, alkalinity and Ca(OH)₂ microparticles had detrimental effects, yet, the latter decreased with the shear-rate. Breakthrough curves for the NaOH and Ca(OH)₂ in xanthan solutions, carried out in the lowest permeability soil (9.9 μm²), demonstrated the excellent transmission of alkalinity, while moderate pressure gradients were applied. Injection velocities ranging from 1.8 to 3.8 m h^-1 are anticipated in the field, given the permeability range from 9.9 to 848.7 μm². Despite a permeability contrast of 8.7 in an anisotropic aquifer model, the NaOH and the Ca(OH)₂ both in xanthan gels spread only 5- and 7-times faster in the higher permeability zone, demonstrating that the delivery was enhanced. Moreover, the alkaline gels which were injected into a high permeability layer under lateral water flow, showed a persistent blocking effect and longevity (timescale of weeks), in contrast to the alkaline solution in absence of xanthan. Kinetics of alkaline dechlorination carried out on the historically contaminated soil, using the Ca(OH)₂ suspension in xanthan solution, showed that HCHs were converted in TCBs by dehydrodechlorination, whereas the latter were then degraded by reductive hydrogenolysis. Degradation kinetics were achieved within 30 h for the major and most reactive fraction of HCHs.

Anti-obesity effect with reduced adverse effect of the co-administration of mini-tablets containing orlistat and mini-tablets containing xanthan gum: In vitro and in vivo evaluation

The purpose of this study was to develop an oral dosage form of orlistat for the treatment of obesity with reduced adverse effects, for example, fatty and oily stool that have been reported to be associated with the mechanism of action of orlistat. Based on the in vitro results obtained in this study, xanthan gum was selected as an oil-entrapping agent. Thus, the co-administration of mini-tablets containing orlistat and mini-tablets containing xanthan gum was proposed as the optimized dosage form for orlistat. The prepared mini-tablets showed an equivalent drug release profile with a similarity factor value, f₂, more than 50 to that of commercially marketed orlistat immediate-release capsules, Xenical® capsules. In addition, the optimized formulation also showed the in vivo anti-obesity effects similar to those of Xenical® capsules. In particular, the analysis of feces excreted by Sprague-Dawley rats revealed that the optimized formulation resulted in significantly less oily stool, steatorrhea, than Xenical® capsules (P < 0.05). Consequently, the proposed formulation, the co-administration of mini-tablets containing orlistat and mini-tablets containing xanthan gum, may be considered as a promising anti-obesity treatment with reduced adverse effects related to orlistat.

Concentrated O/W emulsions formulated by binary and ternary mixtures of sodium caseinate, xanthan and guar gums: rheological properties, microstructure, and stability

The effects of xanthan gum (XG) (0, 0.3, 0.6 wt%), guar gum (GG) (0, 0.3, 0.6 wt%) and XG:GG mixtures (0.3-0.3, 0.3-0.6, 0.6-0.3 and 0.6-0.6 wt%) on the physical stability of sodium caseinate (CN) stabilized concentrated O/W emulsions (φoil = 0.6) were examined. The emulsion stability, microstructure, droplets size distribution, and rheological properties were evaluated. The findings showed that with increasing total gum concentration up to 0.6% droplets size and emulsion instability significantly decreased (p < 0.05). The emulsion containing a ternary mixture of CN:XG:GG at total gum concentration (0.6%) with a mixing ratio of 0.3:0.3 XG:GG exhibited the best stability with the highest ESI value (98.3%). Above the critical concentration, an excessive increase in storage modulus led to a significant increase in droplet size and emulsion instability. In brief, concentrated emulsions stabilized by binary and ternary mixtures (CN/XG/GG) may be applicable in special food like heavy cream and as a template for fabricating oleogels.

Effect of ibuprofen entrapment procedure on physicochemical and controlled drug release performances of chitosan/xanthan gum polyelectrolyte complexes

The effect of the entrapment procedure of a poorly water soluble drug (ibuprofen) on physicochemical and drug release performances of chitosan/xanthan polyelectrolyte complexes (PECs) was investigated to achieve controlled drug release as the ultimate goal. The formation of PECs for two drug entrapment procedures (before or after the mixing of polymers) at pH 4.6 and 5.6 and three chitosan-to-xanthan mass ratios (1:1, 1:2 and 1:3) was observed by continuous decrease in conductivity during the PECs formation and increased apparent viscosity and hysteresis values. The most extensive crosslinking was observed with ibuprofen added before the PECs formation at pH 4.6 and chitosan-to-xanthan mass ratio 1:1. The PECs prepared at polymers' mass ratios 1:2 and 1:3 had higher yield and drug entrapment efficiency. DSC and FT-IR analysis confirmed ibuprofen entrapment in PECs and the partial disruption of its crystallinity. All ibuprofen release profiles were similar, with 60-70% of drug released after 12 h, mainly by diffusion, but erosion and polymer chain relaxation were also included. Potentially optimal can be considered the PEC prepared at pH 4.6, ibuprofen entrapped before the mixing of polymers at chitosan-to-xanthan mass ratio 1:2, which provided controlled drug release by zero-order kinetics, high yield, and drug entrapment efficiency.

NMR Relaxometry and magnetic resonance imaging as tools to determine the emulsifying characteristics of quince seed powder in emulsions and hydrogels

Quince seed powder (QSP) is known to exhibit emulsification properties and could be used as a natural emulsifier in colloidal food systems. In this study, emulsion-based alginate hydrogels were formulated using QSP and xanthan gum (XG) as stabilizers. The objective of the study was to show the emulsifying power of QSP in emulsions and their hydrogels using Time Domain (TD) NMR Relaxometry and Magnetic Resonance Imaging (MRI). Rheology and mean particle size measurements for emulsions and scanning electron microscope (SEM) experiments for hydrogels were further conducted as complementary methods. QSP containing emulsions were found to have longer T₂ relaxation times than XG samples (p < 0.05). Addition of either QSP or XG produced a more pseudoplastic flow behavior (p < 0.05) on the emulsions. Relaxation times were also obtained by MR images through T₂ maps. Relaxation decay curves showed the presence of two proton compartments in hydrogels; protons associated with the polymer matrix and protons interacting with the oil phase. The contribution of the first proton pools was the largest in QSP hydrogels confirmed by the lowest standard deviation in the T₂ maps. This behavior was explained by the emulsification ability of QSP. Results showed that NMR Relaxometry and MR images could be used to understand the emulsifying nature of QSP and many other hydrocolloids.

Effect of xanthan gum-based food thickeners on the dissolution profile of fluoroquinolones oral formulations

Background

Xanthan gum-based food thickeners (XG-FTs) are often ingested by patients with dysphagia to prevent aspiration during drug treatment. Reportedly, XG-FTs affect tablet disintegration, drug dissolution rates, and reduce the efficacy of postprandial antihyperglycemic agents. The absorption rate and quantity of fluoroquinolone antimicrobial agents correlate with drug efficacy, raising concern about the impact of XG-FTs. Previously, we reported that film-coated tablets were less susceptible to the effects of XG-FT than conventional and orally disintegrating tablets. Here, we compare the effect of XG-FTs on dissolution profiles of three oral fluoroquinolone-based film-coated tablets by evaluating the dissolution of crushed products, fine granules, and film-coated fine granules.

Methods

We examined formulations of tosufloxacin tosylate monohydrate (TFLX), levofloxacin hemihydrate (LVFX), and ciprofloxacin hydrochloride hydrate (CPFX). The formulations were immersed in 20 mL of 1.5% (w/v) XG-FT aqueous solution for 2.5 min followed by a dissolution test using the paddle method according to the Japanese Pharmacopoeia (dissolution test solution pH 1.2; volume 900 mL; temperature 37 ± 0.5 °C). The dissolution profile was evaluated according to the dissolution quantity indicated in product specifications and guidelines for bioequivalence testing of generic drugs. The 15-min mean dissolution rate was determined for a formulation immersed in 1.5% (w/v) XG-FT aqueous solution and compared with that for a non-immersed formulation (control). Fluoroquinolone film-coated tablets were mixed with starch-based FTs, guar gum-based FTs, or XG-FTs to observe their appearances.

Results

The dissolution profile of LVFX film-coated tablets was not affected by XG-FTs, but the dissolution of TFLX and CPFX was delayed. For crushed film-coated tablets, the 15-min mean dissolution rate was significantly delayed for all three fluoroquinolones when compared with that of uncrushed products. The dissolution profile of TFLX film-coated fine granules was unchanged by XG-FTs. CPFX film-coated tablets and crushed products produced a gel-like precipitate when mixed with XG-FTs and failed to meet product-dissolution specifications. A gel-like precipitate was also observed with guar gum-based FTs.

Conclusion

The effect of XG-FTs on the dissolution profile of film-coated fluoroquinolone formulations varied depending on the formulation. The CPFX formulation formed a gel-like precipitate when immersed in XG-FTs resulting in a significantly delayed dissolution.

Critical overlap concentration and intrinsic viscosity data of xanthan gum aqueous solutions in dimethyl sulfoxide

This is the supplementary information of the research paper “Haemodynamics around confined microscopic cylinders” by Rodrigues et al. [1]. The critical overlap concentration of entanglement of polymer coils indicates whether a polymer solution is dilute or semidilute. Here, the reader will find the determination of c* for xanthan gum aqueous solutions in 52 wt.% of dimethyl sulfoxide, often used as non-particulate blood analogues. From the shear flow curves of a dilution series of the polymer the zero-shear viscosities η0 were obtained, allowing us to estimate the intrinsic viscosity [η] based on the xanthan gum concentration of the fluids. Two methodologies for doing so are described: using information from multi-concentration measurements and from a single polymer solution (rough estimate). With the intrinsic viscosity the determination of c* is straightforward.

Physicochemical characterization of protein isolates of amaranth and common bean and a study of their compatibility with xanthan gum

Vegetables are considered to be a sustainable source of promising biomaterials such as proteins and polysaccharides. In this study, four protein isolates (amaranth protein isolate API, amaranth globulin-rich protein isolate AGR, bean protein isolate BPI, and bean phaseolin-rich protein isolate BPR) were structurally characterized under different pH conditions (2-12) and their compatibility behavior with xanthan gum (XG) in aqueous medium was described. All protein isolates showed β turn and β sheet (78.24-81.11%), as the major secondary structures without statistically significant difference under the pH conditions surveyed. Protein isolates show solubility at pH ≤ 3 (40.4-85.1%) and pH ≥ 8 (57.6-99.9%) and surface hydrophobicity results suggest protein denaturation at pH ≤ 3. In the compatibility study, API/XG ratios between 1:1 and 5:1 at pH from 7 to 9 and the BPI/XG ratios from 1:1 to 20:1 at pH 7 form gels that do not require heating nor crosslinking agent addition. Zeta potential results, on the other hand, evidenced that formation of gels is driven by attractive electrostatic interaction of the charged regions of both biopolymers and intermolecular interactions such as hydrogen bonds.

Modified xanthan gum for methyl orange uptake: Kinetic, isotherm, and thermodynamic behaviors

A novel hydrogel, named XGTTE, was prepared by modification of acrylamide and trimethylolpropane triglycidyl ether (TTE) on xanthan gum (XG). XGTTE was utilized as an adsorbent to remove methyl orange (MO) from an aqueous solution. Functional groups present in the external surface of XGTTE, such as carboxyl, hydroxyl, and amino groups, were identified, and these functional groups are responsible for the occurrence of the mechanism for MO adsorption. The structure of XGTTE after MO adsorption became more disordered. The adsorption dynamics and isotherms of MO onto XGTTE conformed well to the pseudo-second-order kinetics and the Freundlich equation, indicated that the adsorption included physical and chemical adsorption, with electrostatic interaction and hydrogen-bonding interaction. The calculated values of the thermodynamic parameters, such as changes in enthalpy (ΔH) and entropy (ΔS) were 27.30 kJ/mol and 125.63 J/mol/K, respectively. The changes in free energy (ΔG) were - 9.53 kJ/mol (293.15 K), -10.16 kJ/mol (298.15 K), -10.78 kJ/mol (303.15 K), -11.41 kJ/mol (308.15 K), and - 12.04 kJ/mol (313.15 K), respectively, indicating the adsorption process is endothermic, spontaneous, and entropic. The maximum adsorption capacities of XGTTE2, XGTTE3, XGTTE4, XGTTE5, and XGTTE6 for MO were 18.62 ± 0.99, 21.92 ± 0.84, 28.60 ± 0.84, 29.56 ± 0.99, and 12.38 ± 0.84 mg/g, respectively.

Effects of xanthan gum, canning and storage period on fatty acid profile and cholesterol oxidation of restructured low-fat meat product of India

This study evaluated the impact of xanthan gum (XG), canning and storage on fatty acids (FAs) contents and formation of cholesterol oxidation products (COPs) in low-fat meat product (goshtaba) of Jammu and Kashmir (J&K), India. The FAs composition i.e. saturated FAs, monounsaturated FAs, polyunsaturated FAs and trans FAs during processing and storage showed non-significant difference in all goshtaba products (P > 0.05). The cholesterol content decreased significantly after canning in all products (P < 0.05) while, maximum reduction was observed in high-fat goshtaba (HFC). During storage all products exhibited significant decrease in cholesterol upto 6th month, thereafter showed non-significant variation. The COPs determined were 7-β-OH-ch, 5-ch-3β-ol-7-one and 25-OH-ch. After canning two COPs (7-β-OH-ch, 5-ch-3β-ol-7-one) were produced in all products. But during storage there was formation of 25-OH-ch, increase in 7-β-OH-ch and decrease in 5-ch-3β-ol-7-one and lower COPs were observed in low-fat goshtaba containing 1.5% XG. The results concluded that fat replacer (XG), processing and storage had no significant effect on the FAs compositions of all goshtaba products including HFC. However, cholesterol content exhibited significant variation and minimum reduction in cholesterol and formation of lower COPs were observed in low-fat goshtaba formulated with 1.5% XG.

Marine-inspired molecular mimicry generates a drug-free, but immunogenic hydrogel adhesive protecting surgical anastomosis

Herein, we report the synthesis of a biomimic hydrogel adhesive that addresses the poor healing of surgical anastomosis. Dopamine-conjugated xanthan gum (Da-g-Xan) is fabricated using deep insights into the molecular similarity between mussels' adhesive and dopamine as well as the structural similarity between barnacle cement proteins and xanthan gum. The hydrogel mimics marine animals’ adherence to wet tissue surfaces. Upon applying this adhesive to colonic anastomosis in a rat model, protective effects were shown by significantly improving the bursting pressure. Mechanistically, the architecture of Da-g-Xan hydrogel is maintained by dynamic intermolecular hydrogen bonds that allow the quick release of Da-g-Xan. The free Da-g-Xan can regulate the inflammatory status and induce type 2 macrophage polarization (M2) by specifically interacting with mannose receptors (CD206) revealed by RNA-sequencing and molecular binding assays. Consequently, an appropriate microenvironment for tissue healing is created by the secretion of chemokines and growth factors from M2 macrophages, strengthening the fibroblast migration and proliferation, collagen synthesis and epithelial vascularization. Overall, this study demonstrates an unprecedented strategy for generating an adhesive by synergistic mimicry inspired by two marine animals, and the results show that the Da-g-Xan adhesive augments native tissue regenerative responses, thus enabling enhanced recovery following surgical anastomosis.

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Dual-biomimic conjugates, Da-g-Xan, are synthesized.

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Da-g-Xan adhesive hydrogels are degradable, self-healing, and injectable.

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Released Da-g-Xan induces type 2 macrophage polarizations by specifically interacting with mannose receptors.

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Paracrine action by the type 2 macrophage polarizations promotes the surgical anastomosis healing.

Protective effect and mechanism of action of xanthan gum on the color stability of black rice anthocyanins in model beverage systems

We investigated the effect and mechanism of action of xanthan gum (XG) on the color stability of black rice anthocyanins (BRA) in model beverage systems (pH 3.0) containing l-ascorbic acid under different conditions. The color stability of BRA was significantly enhanced in the presence of XG under accelerated storage conditions (40 °C), particularly at 0.25% (w/v). The degradation of BRA followed a first-order reaction rate (R² > 0.89) during storage and thermal processing conditions. The addition of XG effectively improved the storage stability of BRA in the presence of l-ascorbic acid, particularly at 4 °C in the dark. Moreover, the thermal stability of BRA was enhanced by XG under thermal treatment (80 °C, 90 °C and 100 °C). The FTIR spectrum, X-ray diffraction and molecular simulation results showed that the interaction between XG and BRA was driven mainly by hydrogen bonds and hydrophobic interactions, leading to the increased stability of BRA. Our study demonstrated the benefits of using XG to improve the color stability of BRA in model beverage systems, further expanding the practical application of XG in anthocyanin-rich beverages.

Xanthan gum as a carrier for bacterial cell entrapment: Developing a novel immobilised biocatalyst

Xanthan gum (XAN) is a widely used polysaccharide in various industries. Because of its unique properties, in this study, an attempt was made to adopt the procedure of xanthan gum cross-linking for the entrapment of bacterial cells that are able to biodegrade naproxen. The developed procedure proved to be completely neutral for Bacillus thuringiensis B1(2015b) cells, which demonstrated a survival rate of 99%. A negative impact of entrapment was noted for strain Planococcus sp. S5, which showed a survival rate in the 93-51% range. To achieve good mechanical properties of the composites, they were additionally hardened using polydopamine (PDA). XAN/PDA composites revealed a high stability in a wide range of pH, and their sorption capacity included both cationic and anionic molecules. Analysis of the survival rate during storage at 4 °C in 0.9% NaCl showed that, after 35 days, 98-99% of B1(2015b) and 47% of S5 cells entrapped in XAN/PDA remained alive. This study also presents the results of naproxen biodegradation conducted using XAN/PDA/B1(2015b) in a trickling filter with autochthonous microflora. Hence, owing to the significant acceleration of drug biodegradation (1 mg/L in 14 days) and the chemical oxygen demand removal, the entrapped B1(2015b) cells in XAN/PDA composites showed a promising potential in bioremediation studies and industrial applications.

Hydrophobized cellulose nanocrystals enhance xanthan and locust bean gum network properties in gels and emulsions

Locust bean/xanthan gum (LBG/XG) synergistic networks have previously been well studied, with evidence that junction zones between the two polymers result in hydrophobic domains. Here we report on the effect of both hydrophilic and hydrophobic cellulose nanocrystals (CNCs) on the rheological properties of the individual gums, the gum networks, and emulsion gels consisting of the gum network and corn oil. We also take advantage of differences in the autofluorescent spectra for each of the components to map their distribution within the gel and emulsion gel systems. Whilst both types of CNC confer thermal stability to the systems, hydrophilic CNCs induce minor changes in rheological properties of synergistic gels and prove to be detrimental to the stability of the emulsion gels. In contrast, hydrophobic CNCs associate with the LBG/XG network, affecting the rheological response. Their inclusion in the emulsion gel system results in smaller, more homogeneously distributed oil droplets with a resultant increase in the storage modulus by an order of magnitude compared to the CNC-free and hydrophilic CNC systems. We conclude that hydrophobic CNCs play a critical role in stabilising LBG/XG network gels and emulsions.

Inflammatory Effects of Thickened Water on the Lungs in a Murine Model of Recurrent Aspiration

OBJECTIVE

Liquid thickeners are commonly recommended in individuals with dysphagia and recurrent aspiration as a strategy for pneumonia prevention. The goal of this study was to examine the effects of small amounts of aspirated liquid thickener on the lungs.

STUDY DESIGN

Animal model. Prospective small animal clinical trial.

METHODS

Adult Sprague Dawley rats (n = 19) were divided into two groups and underwent three intratracheal instillations of either xanthan gum-based nectar-thick water (0.1-0.25 mL/kg) or water-only control over the course of 8 days. Blood was collected from a peripheral vein on days 1 and 8 and submitted for complete blood count (CBC) analysis. Rats were euthanized 10 days after the last instillation, and the lungs were harvested. Histopathology was conducted on lung specimens by a blinded licensed veterinary pathologist and scored for evidence of lung injury and pneumonia.

RESULTS

Fifteen animals (8 nectar-thickener group, 7 control group) survived until the endpoint of the study (day 18). Serum CBC did not show abnormalities at any timepoint in either group. Histological evidence of lung inflammation and edema were significantly greater in the nectar-thick group compared to controls (P < .05). Signs of inflammation included aggregates of foamy macrophages, expansion of bronchiolar lymphoid tissue, and large numbers of eosinophilic intraalveolar crystals. Histiocytic and neutrophilic pneumonia was noted in one animal that received thickened liquids.

CONCLUSION

Recurrent aspiration of small amounts of thickened water resulted in significant pulmonary inflammation in a murine model of aspiration. Results of this study support the need for further investigation of liquid thickener safety and its efficacy in reducing the pulmonary complications of swallowing disorders.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:1223-1228, 2021.

Xanthan gum as an alternative to replace the fat for coating and flavoring the extruded snacks

Food industries adapt their products and processes to the needs and desires of consumers. Extruded snacks include 10-20% fat sprinkled to fix flavors, seasonings, and salt. Considering the need to flavor snacks and simultaneously reduce the intake of calories, a polysaccharide is proposed in this study as a fat replacer. Impact of aqueous xanthan gum (Xg) solutions (0.25, 0.5, 1.0%) under two pH conditions (3.5 and 7.0) on structural and sensory characteristics of extruded snacks was analyzed. Rheological features of the coating solutions, as flow behaviour and viscoelastic profile (storage and loss moduli), were assessed. Texture analysis, to evaluate the snacks firmness and moisture content, water activity, retraction, and agglomeration index of the coated snacks, were also evaluated. Results for the aqueous Xg coatings were very encouraging showing good coating properties, not damaging the texture of the extrudates or causing agglomeration. Sensory analysis reflected a good overall acceptability of these snacks, as compared to oil-coated snacks. Therefore, xanthan gum should be used by the industry, to replace fat, on extruded snacks flavor coating solutions.

Formulation, development and characterization of a novel functional fruit snack based on fig (Ficus carica L.) coated with sugar-free chocolate

The aim of the present investigation was to explore the possibility of developing a fruit snack formulation based on dried fig powder and chocolate-coated. Dried Fig (Ficus carica L.) powder with a maximum particle size of 354 μm and the lowest compaction force was formulated as the core. Persian gum was prepared at the concentrations of 1.5, 2 and 2.5% and xanthan gum was prepared at the levels of 0.25, 0.39 and 0.54% as the middle layer to the coating of the core. Regarding rheological assessments, sugar-free chocolate containing 29.3% isomalt was selected for the coating of the outer chocolate shell in the entitled snack. Textural analysis showed that coating of the core with hydrocolloids decreased hardness and adhesiveness of the samples (p < 0.05). It was also observed that increasing the xanthan gum and Persian gum concentration led to the reduction of adhesiveness in the snacks (p < 0.05). Coating of cores with hydrocolloids resulted in lower thickness of the chocolate outer shell, as well (p < 0.05). Results of the sensory evaluation tests demonstrated that, the samples with hydrocolloid coating were the most preferred ones by the panelists.