Rheological Properties of Aqueous Dispersions of Xanthan Gum Containing Different Chloride Salts Are Impacted by both Sizes and Net Electric Charges of the Cations

Galván, Zoila Rosa Nieto; Soares, Lucas de Souza; Medeiros, Éber Antônio Alves; Soares, Nilda de Fátima Ferreira; Ramos, Afonso Mota; Coimbra, Jane Sélia dos Reis; Oliveira, Eduardo Basílio de

doi:10.1007/s11483-018-9524-9

Cited by 23 publications

(10 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Of each single component, xanthan had the highest PSD ( Figure 2), which is consistent with findings from intrinsic viscosity measurement. There was an increase, though insignificant, in PSD of xanthan with an increase in temperature and time (F 1,2 = 33.50, p = 0.11) which was higher than what was reported previously [35]. From Day 1 to Day 7 and Day 14, PSD of xanthan significantly increased on Day 14 (F 1,2 = 301.41, p = 0.03) but not on Day 7 (F 1,2 = 35.49, p = 0.11) (Figure 2, Supplementary Table S3).…”

Section: Particle Size Distributioncontrasting

confidence: 67%

Clinically Relevant Insulin Degludec and Its Interaction with Polysaccharides: A Biophysical Examination

et al. 2020

View full text Add to dashboard Cite

Protein polysaccharide complexes have been widely studied for multiple industrial applications and are popular due to their biocompatibility. Insulin degludec, an analogue of human insulin, exists as di-hexamer in pharmaceutical formulations and has the potential to form long multi-hexamers in physiological environment, which dissociate into monomers to bind with receptors on the cell membrane. This study involved complexation of two negatively charged bio-polymers xanthan and alginate with clinically-relevant insulin degludec (PIC). The polymeric complexations and interactions were investigated using biophysical methods. Intrinsic viscosity [η] and particle size distribution (PSD) of PIC increased significantly with an increase in temperature, contrary to the individual components indicating possible interactions. [η] trend was X > XA > PIC > A > IDeg. PSD trend was X > A > IDeg > XA > PIC. Zeta (ζ)-potential (with general trend of IDeg < A < XA < X ≈ PIC) revealed stable interaction at lower temperature which gradually changed with an increase in temperature. Likewise, sedimentation velocity indicated stable complexation at lower temperature. With an increase in time and temperature, changes in the number of peaks and area under curve were observed for PIC. Conclusively, stable complexation occurred among the three polymers at 4 • C and 18 • C and the complex dissociated at 37 • C. Therefore, the complex has the potential to be used as a drug delivery vehicle.Polymers 2020, 12, 390 2 of 15 Alginates (A) are linear polymers of 1,4-linked β-D-mannuronic acid residues and 1,4-linked α-L-guluronic residues, containing homo-polymeric sequences [7]. Xanthan (X) is composed of D-glucosyl, D-mannosyl, and D-glucuronyl acid residues in a 2:2:1 molar ratio and variable proportions of O-acetyl and pyruvyl residues. Its main chain consists of β-D-glucose units linked at the 1 and 4 positions. Side-chains consist of a tri-saccharide composed of mannose (β-1,4) glucuronic acid and (β-1,2) mannose, attached to alternate glucose residues in the backbone by α-1,3 linkages [8,9].Xanthan gum and alginate complexes (XA) have been studied previously [10] and used for functional foods [11], tissue engineering [3,12,13] and drug delivery. As negatively charged polymers, xanthan [14][15][16][17] and alginate [18][19][20] have been used separately, and in combination with positively charged polymers such as chitosan, as potential vehicles for insulin delivery.Interactions among different types of protein-polysaccharide complexes (PPCs) have been previously investigated using a variety of methods [21,22]. The formation and dissociation of PPCs and their solubility depend on many factors such as surface charge, pH, temperature and ionic strength of the solvent [23]. These factors greatly influence non-covalent interactions such as electrostatic, H-bonding, hydrophobic, and steric interactions, as well as covalent interactions [24]. Conjugation of polysaccharides with therapeutic proteins is a well-established phenomenon [25]. In particul...

show abstract

Section: Particle Size Distributioncontrasting

confidence: 67%

Clinically Relevant Insulin Degludec and Its Interaction with Polysaccharides: A Biophysical Examination

et al. 2020

View full text Add to dashboard Cite

show abstract

“…As expected, upon a 50% dilution with artificial saliva buffer, the flow curve of 1.0 wt% XG became similar to that of 0.5 wt% XG before dilution (p > 0.05). For instance, the apparent viscosities of 1.0 wt% XG + artificial saliva buffer and 0.5 wt% XG at 100 s -1 were 0.07 Pa s suggesting that the addition of salts, from artificial saliva buffer or mucin did not affect the bulk interactions between XG molecules significantly or lead to further gelation [19,43]. The incorporation of artificial saliva containing α-amylase did not affect the apparent viscosity of XG, as expected from the visual observations (Figures 1, 2Biii) and the viscosity values were one-order of magnitude higher than artificial saliva at 50 s -1 shear rate in contrast to the behaviour of MS (Figures 1, 2Aiii).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…The heteropolysaccharide consists of repeating glucose units, alpha-D-mannose with an acetyl group, beta-D-glucuronic acid, and beta-D-mannose linked to pyruvate resulting in a high molecular weight macromolecule. The large number of side chains results in the stability of xanthan gum towards pH, ionic strength and temperature, allowing xanthan gum to be used as a commercial dysphagia thickener, either by itself or in combination with other ingredients [9,12,[18][19][20][21].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Gellan gum: A new member in the dysphagia thickener family

et al. 2019

View full text Add to dashboard Cite

Please cite this article as: O. Torres, A. Yamada, N.M. Rigby, et al., Gellan gum: A new member in the dysphagia thickener family, Biotribology, https://doi. AbstractIn this study, gellan gum (GG) (0.075-0.3 wt%) is proposed as a new dysphagia thickener and compared against commercial starch-based thickeners (modified starch with or without gums, 5 wt%) and xanthan gum (XG, 0.5-1.0 wt%) using apparent viscosity, oral tribology using polydimethylsiloxane (PDMS) ball-on-disc set up and ζ-potential measurements. The measurements were conducted in presence of artificial saliva containing mucin with or without α-amylase at 37 ○ C. Viscosity results suggested that the commercial starch-based thickeners behaved like water in orally relevant shear, largely associated with the hydrolysis of modified starch by α-amylase, while, XG and GG showed no responsiveness to α-amylase.In the case of oral tribology, artificial saliva containing mucin adsorbed to the PDMS surfaces reducing friction as compared to water. The increase in boundary friction coefficients in commercial starch-based thickeners was likely associated with α-amylaseinduced hydrolysis, increasing the PDMS-PDMS asperity contacts. Interestingly, the tribological behaviour of XG and GG was dictated mainly by viscous lubrication. However, in simulated oral conditions, the increase in friction coefficients in presence of XG and GG was influenced by depletion of artificial saliva from the PDMS surfaces due to electrostatic interaction between the gums and mucin. A combination of rheological and tribological techniques in orally relevant conditions appears as a reliable approach to understand the potential of GG (0.3 wt%) to act as a dysphagia thickener that offers similar mechanical properties as XG (1.0 wt%) at a lower concentration. Extensional viscosity measurement of GG is needed to understand its applications in dysphagia management.

show abstract

“…The total amount of substituents highly depends on the used strain as well as culture conditions and can range from 6.5 % to 13 % for acetate and 2.8 % to 14 % for pyruvate (Abbaszadeh et al, 2015;Garcıa-Ochoa, Santos, Casas, & Gomez, 2000;Li & Feke, 2015). While xanthan exhibits excellent thickening properties over a wide range of pH and temperature (Garcıa-Ochoa et al, 2000), the influence of salts on its rheological behavior is remarkable and has been widely studied (Bergmann, Furth, & Mayer, 2008;Callet, Milas, & Rinaudo, 1987;Dário, Hortêncio, Sierakowski, Neto, & Petri, 2011;Galván et al, 2018;Xu, Dong, Gong, Sun, & Li, 2015). Because of the regioselectivity of the transferases, it is possible, to create xanthan-variants with specific acetylation and pyruvylation-patterns by deletions of the genes gumF, gumG and gumL and combinations thereof.…”

Section: Accepted Manuscriptmentioning

confidence: 99%