Studies on dilute solutions and dispersion of the polysaccharide from Xanthomonas campestris NRRL B-1459

Dintzis, Frederick R.; Babcock, G. E.; Tobin, R.

doi:10.1016/s0008-6215(00)80832-0

Cited by 85 publications

(14 citation statements)

References 7 publications

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“…The behaviour and properties of xanthan solutions at different concentration regimes have been studied extensively [7], [29], [31]–[34]. The diffusion coefficient versus the concentration curve showed a plateau in the diffusion coefficient as the concentrations approached zero, at 0.9 µm 2 .s −1 , Fig.…”

Section: Resultsmentioning

confidence: 99%

Concentration Regimes of Biopolymers Xanthan, Tara, and Clairana, Comparing Dynamic Light Scattering and Distribution of Relaxation Time

et al. 2013

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The aim of this work was to evaluate the utilization of analysis of the distribution of relaxation time (DRT) using a dynamic light back-scattering technique as alternative method for the determination of the concentration regimes in aqueous solutions of biopolymers (xanthan, clairana and tara gums) by an analysis of the overlap (c*) and aggregation (c**) concentrations. The diffusion coefficients were obtained over a range of concentrations for each biopolymer using two methods. The first method analysed the behaviour of the diffusion coefficient as a function of the concentration of the gum solution. This method is based on the analysis of the diffusion coefficient versus the concentration curve. Using the slope of the curves, it was possible to determine the c* and c** for xanthan and tara gum. However, it was not possible to determine the concentration regimes for clairana using this method. The second method was based on an analysis of the DRTs, which showed different numbers of relaxation modes. It was observed that the concentrations at which the number of modes changed corresponded to the c* and c**. Thus, the DRT technique provided an alternative method for the determination of the critical concentrations of biopolymers.

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Section: Resultsmentioning

confidence: 99%

Concentration Regimes of Biopolymers Xanthan, Tara, and Clairana, Comparing Dynamic Light Scattering and Distribution of Relaxation Time

et al. 2013

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“…Two mayonnaise formulas were prepared in three replicates; the viscosity of each formula was measured by the Brookfield viscometer model RVT and was compared (Dintzis et al 1970). No difference was observed at the probability level of 5%.…”

Section: Resultsmentioning

confidence: 99%

Bioconversion of Sugar-Beet Molasses Into Xanthan Gum

Moosavi¹,

Karbassi²

2010

Journal of Food Processing and Preservation

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The possibility of using sugar‐beet molasses as the sole carbon source by different strains of Xanthomonas was evaluated in terms of xanthan gum production. Highest yield of xanthan was obtained at a 50 g/kg sucrose concentration in a medium based on sugar‐beet molasses by the wild‐type isolate Xanthomonas campestris pv. campestris (19.8 g/L) (P < 0.05). The apparent viscosity of the xanthan produced by wild‐type isolates were compared with the commercially used gum in a mayonnaise product. No difference was shown. It seems that less expensive substrates could be a suitable and cost‐effective alternative for xanthan gum production. PRACTICAL APPLICATIONS Molasses is a co‐product of sugar production, both from sugar beet as well as from sugar cane, and is defined as the runoff syrup from the final stage of crystallization, from which further crystallization of sugar is uneconomical. Since this industrial by product constitutes valuable source of growth substances it is widely used as a substrate in microbial fermentations. Xanthan gum is a water‐soluble hetero‐polysaccharide that is produced industrially from sucrose or glucose by fermentation using the gram‐negative bacterium X. campestris. Commercially available xanthan gum is relatively expensive due to glucose or sucrose being used as the sole carbon source and the very stringent purity standards of the Food and Drug Administration for foods. Based on a preliminary analysis, the use of sugar beet molasses for xanthan gum production has the potential to be a cost‐effective supplemental substrate specially when non food grade gum is to be produced.

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“…Urea also disrupts nucleic acids stability – DNA and RNA – (Hackl & Blagoi, 2004; Shcherbakova & Brenowitz, 2005) by influencing the hydrogen bonding arrangement in the base pairs. In the case of polysaccharides higher amounts of urea thwart gelation in amylose (Welsh, Bailey, Chandarana & Norris, 1982), xanthan (Dintzis, Babcock & Tobin, 1970; Frangou, Morris, Rees, Richardson & Rossmurphy, 1982), iota-carrageenan (Morris & Belton, 1982), kappa-carrageenan (Nishinari, Watase, Williams & Phillips, 1990) and agarose (Watase & Nishinari, 1986). However, urea in association with sodium hydroxide is reported to be beneficial for studying the functional behaviors of water insoluble cellulose (Cai & Zhang, 2006) and chitosan (Tsaih & Chen, 1997) as well as those of water soluble glucan (Zhang, Zhang & Cheng, 2000) and aeromoans gum (Xu, Zhang & Zhang, 2005) aggregates.…”

Section: Discussionmentioning

confidence: 99%

Impact of urea on the three-dimensional structure, viscoelastic and thermal behavior of iota-carrageenan

Patel

Campanella

Janaswamy

2013

Carbohydrate Polymers

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Urea breaks hydrogen bonds among biopolymers leading to structural destabilization. In the case of hydrocolloids urea addition is thought to impact gelation. Detailed information about its pertinent role on influencing the structure-function relationships of hydrocolloids is still elusive, however. The present investigation is aimed at delineating hydrocolloids structural behavior in the presence of urea employing iota-carrageenan as a model system. X-ray fiber diffraction, rheological and thermal properties of two iota-carrageenan solutions with weight concentrations 4.5 and 6.0% w/w at two urea molar concentrations (0.5 and 2.0 M) with and without heat treatments have been analyzed. X-ray results suggest that the canonical double helical structural arrangement of iota-carrageenan is maintained even after urea addition. However, improved crystallinity, ordering and altered unit cell dimensions especially with heat treatments of the binary mixtures indicate the promotion of favorable interactions among carrageenan helices in the presence of urea. Increased elastic modulus and onset temperature of melting endotherm with the heat treatment compared to cold addition further attests the X-ray observations of enhanced structural ordering. Overall, results suggest that urea molecules synergistically aid iota-carrageenan interactions and stabilize structure of junction zones. Our findings are deemed to be helpful in the design and development of novel non-food applications of hydrocolloids.

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Studies on dilute solutions and dispersion of the polysaccharide from Xanthomonas campestris NRRL B-1459

Cited by 85 publications

References 7 publications

Concentration Regimes of Biopolymers Xanthan, Tara, and Clairana, Comparing Dynamic Light Scattering and Distribution of Relaxation Time

Concentration Regimes of Biopolymers Xanthan, Tara, and Clairana, Comparing Dynamic Light Scattering and Distribution of Relaxation Time

Bioconversion of Sugar-Beet Molasses Into Xanthan Gum

Impact of urea on the three-dimensional structure, viscoelastic and thermal behavior of iota-carrageenan

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