Aggregation of Aeromonas Gum in Aqueous Solution

Zhang, Lina; Xu, Xiaojuan; Jiang, Guowen; Iijima, Hideki; Tsuchiya, Hiromichi

doi:10.1295/polymj.31.150

Cited by 16 publications

(12 citation statements)

References 14 publications

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“…The previous A gum fraction (A-5), 14 which was fractionated by reprecipitation from pure water as a solvent to isopropanol as a precipitant, was used for the present work. The weight-average molecular weight (M w ) and intrinsic viscosity ( …”

Section: Experimental Samplementioning

confidence: 99%

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Urea/NaOH aqueous solution as new solvent of aeromonas gum

Zhang

2005

J of Applied Polymer Sci

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Aeromonas (A) gum, an acidic heteropolysaccharide, formed aggregates easily in NaCl aqueous solution. A novel solvent of the A gum, which can prevent aggregation, was found to be 0.20M urea/0.25M NaOH aqueous solution. The weight-average molecular weight (M w ), radius of gyration (͗s 2 ͘ 1/2 ), and intrinsic viscosity ([]) of the samples were determined in 0.20M urea/0.25M NaOH aqueous solution at 25°C by light scattering (M w , ͗s 2 ͘ 1/2 ) and viscometry ([]). The values of M w , ͗s 2 ͘ 1/2 , and [] were close to those in 0.20M lithium chloride/dimethylsulfoxide, in which the A gum exists as a semiflexible single chain, implying the same conformation for the A gum in 0.20M urea/0.25M NaOH aqueous solution. The results revealed that 0.20M urea/0.25M NaOH aqueous solution is a good solvent, which effectively avoids the aggregates of the A gum in aqueous solution. Moreover, it can be used to investigate the solution properties and chain conformation of water-insoluble polysaccharides or the polysaccharides that are easily aggregated in aqueous systems.

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Section: Experimental Samplementioning

confidence: 99%

“…13 Recently, we have confirmed that the A gum forms aggregates in a salt aqueous solution 14 -16 and the aggregates are broken into single chains in cadoxen 14 and dimethylsulfoxide (DMSO) containing 0.20M lithium chloride (LiCl). [17][18] However, cadoxen is prepared with cadmium oxidation and it is poisonous.…”

Section: Introductionmentioning

confidence: 96%

Urea/NaOH aqueous solution as new solvent of aeromonas gum

Zhang

2005

J of Applied Polymer Sci

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“…[13][14][15] Aeromonas gum, a stabilizer and thickening agent of food, exists as an aggregate in 0.5 M NaCl aqueous solution and as a single chain in cadoxen. 7 These results indicated that polysaccharides have generally a tendency to aggregate in aqueous solution because of the abundance of inter-chain hydrogen bonds. In this work, components, apparent weight-average molecular weight M w , mean molecular size, aggregation behavior of E gum in aqueous solution were determined by the IR, high-performance liquid chromatography (HPLC), static and dynamic light scattering, and GPC.…”

Section: Introductionmentioning

confidence: 98%

“…and the aggregation resulted from inter-chain interaction. 6,7 Recently, much attention has been paid to the polymer aggregation, which play an important role in the thickening, micellization, gelation and microencapsulation etc.. The aggregation process in dilute solution, 8 aggregation mechanism, 9 aggregation behavior, 10 and the effects of temperature and polymer concentration on the aggregation of polymers 5,11,12 have been studied by static and dynamic light scattering, combining gel permeation chromatography (GPC) with infrared (IR) spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Molecular size and aggregation behavior of Erwinia gum in aqueous solution

Zhang¹,

Xu²,

Zhang³

et al. 2000

J. Appl. Polym. Sci.

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Erwinia (E) gum, a stabilizer and thickening agent of food, is composed of glucose, fucose, galactose, and glucuronic acid (1 : 0.1 : 0.05 : 0.3 by molar ratio). The apparent weight-average molecular weight M w and intrinsic viscosity [] in 0.2 M NaCl aqueous solution were measured to be 7.83 ϫ 10 5 and 268 mL g Ϫ1 , respectively, by light scattering and viscometry. The aggregation behavior of E gum in aqueous solution was investigated by gel permeation chromatography (GPC) and dynamic light scattering. The results showed that 7.5% E gum exists as an aggregate, whose diameter is 12 times greater than single-stranded chain, in aqueous solution at 25°C, and the aggregates' content decreased with increasing temperature or decreasing polymer concentration. The aggregates at higher temperature were more readily broken than in exceeding dilute solution. GPC analysis proved that a significant shoulder, corresponding to a fraction of higher molecular weight due to chain aggregation, appeared in the chromatogram of E gum in 0.05 M KH 2 PO 4 /5.7 ϫ 10 Ϫ3 M NaOH aqueous solution (pH 6.0) at 35°C, and decreased with increasing temperature, finally disappeared at 90°C. The disaggregation process of E gum in aqueous solution can be described as follows: with increasing temperature, large aggregates first were changed into the middle, then disrupted step by step into single-stranded chains.

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“…A gum is composed of xylose, mannose, galactose, glucose, and mannuronic acid, and E gum contains fucose, galatose, glucose and glucuronic acid. 3,4 The various extracellular polysaccharides produced from Aeromonas solmvnicida and Erwinia chrysanthemi have been reported 5,6 ; however, studies relating to miscibility are rarely published. It is well known that xanthan and pectin are normally used as additives for foods and cosmetics.…”

Section: Introductionmentioning

confidence: 99%

Miscibility of blends ofAeromonas gum orErwinia gum with other polysaccharides

Yang

Zhang

Feng

et al. 1999

J. Appl. Polym. Sci.

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Aeromonas (A) gum and Erwinia (E) gum are acidic heteropolysaccharides, which exist in water as expanded chains caused by the electrostatic repulsion between the charged groups. A modified approach, which was suggested to estimate miscibility of stiff polymer in our previous study, was used to determine miscibility parameter for blends between A gum or E gum with other polysaccharides, by using viscometry in aqueous 0.1M NaCl solution. When weight ratios of E gum/pectin were in the range of 3 : 7 ϳ 7 : 3, the blends in aqueous solution are miscible. The blends of A gum/xanthan, A gum/pectin, and E gum/xanthan in aqueous solution are obviously immiscible. When the weight fraction (w 2 ) of A gum or E gum in the mixture solution is 0.7, the predicts that the miscibility of blend films was on the order of E gum/pectin Ͼ E gum/xanthan Ͼ A gum/pectin Ͼ A gum/xanthan. These results are in good agreement with those observed by scanning electron microscopy and Fourier transform IR.

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Aggregation of Aeromonas Gum in Aqueous Solution

Cited by 16 publications

References 14 publications

Urea/NaOH aqueous solution as new solvent of aeromonas gum

Urea/NaOH aqueous solution as new solvent of aeromonas gum

Molecular size and aggregation behavior of Erwinia gum in aqueous solution

Miscibility of blends ofAeromonas gum orErwinia gum with other polysaccharides

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