Influence of the pyruvate content of xanthan on macromolecular association in solution

Smith, Ian H.; Symes, K.C.; Lawson, Christopher J.; Morris, Edwin R.

doi:10.1016/0141-8130(81)90078-7

Cited by 140 publications

(41 citation statements)

References 16 publications

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“…According to Wypych (2005), the proportion of these gums that allows to obtain the maximum strength in the gel is of 50/50 (%, w/w). By using xantham gum with a high content in pyruvirate (44%), macromolecular association with formation of microcrystalline regions is promoted, increasing the polymer-polymer affinity comparatively to the polymersolvent (Smith et al, 1981), and producing a highly thermoresistant gel (Tako, 1991). The interaction between these solutes, added to the pullulan, make the final product more elastic, cohesive, resistant, with improved water retention, reducing syneresis and producing a creamy tactile texture in the mouth (Wypych, 2005).…”

Section: Resultsmentioning

confidence: 99%

Development of a buccal mucoadhesive film for fast dissolution: mathematical rationale, production and physicochemical characterization

et al. 2013

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The validity of a mathematical rationale for preparation of a fast-dissolving buccal mucoadhesive was tested. A buccal mucoadhesive biopolymeric formulation has been developed having pullulan as the main component. The formulation was duly evaluated physicochemically, via assays for intrinsic viscosity (resulting in 71.61 cm 3 g À1 ), differential scanning calorimetry analysis (resulting in a Tg ¼ 63 C), thermogravimetric analysis (244-341 C), moisture content determinations (14%, w/w), dissolution timeframe (41.6 s), mucoadhesion force (40 kg/cm 2 ), scanning electron microscopy analyses (critical ray under 1.0 mm), mechanic strength (tensile strength ¼ 58 N/mm 2 , deformation ¼ 4.4%). The mucoadhesive formulation exhibited important characteristics for a drug carrier, that is, a 6 cm 2 area, a fast dissolution timeframe, an adequate mucoadhesivity, resistance to both oxygen and water vapor penetration, increased viscosity in solution (ranging from 33.2 cm 3 /g to 71.61 cm 3 /g), easy molding, suitable water solubility and transparency.

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Section: Resultsmentioning

confidence: 99%

Development of a buccal mucoadhesive film for fast dissolution: mathematical rationale, production and physicochemical characterization

et al. 2013

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“…Assim, xantanas com alto conteúdo de piruvato (> 4%) apresentam viscosidade superior àquelas com conteúdo inferior de piruvato (0,5 a 3%). Para Smith et al (1981), amostras com alto teor de piruvato aumentam a viscosidade das soluções de xantana na presença de KCl pelo aumento na associação macromolecular. Seus resultados indicam que o substituinte piruvato promove associação e formação da macroestrutura pelo aumento na afinidade polímero-polímero, comparativamente à afinidade polímero-solvente.…”

Section: Influência Da Composição Química Da Xantana Nas Característiunclassified

Goma Xantana: características e condições operacionais de produção

Borges¹,

Vendruscolo²

2008

Semin. Cienc. Biol. Saude

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ResumoGoma xantana é um polissacarídeo extracelular produzido pelas bactérias do gênero Xanthomonas. Sua funcionalidade é uma conseqüência direta de sua estrutura química. Esta estrutura tem sido amplamente estudada por ser passível de mudanças, sendo dependente do microrganismo produtor e das condições operacionais aplicadas durante a fermentação. O trabalho tem como objetivo revisar a influência das condições operacionais de produção de xantana nas características físico-químicas da goma produzida. Palavras-chave: Xantana. Condições operacionais. Composição química. Reologia. AbstractXanthan gum is an extracelullar polysaccharide produced by bacteria of the genus Xanthomonas. Its functionality is a direct consequence of its chemical structure. This structure has been widely studied because it is subject to changes, dependant on the producer microrganism and on the operational conditions applied during the fermentation. The purpose of this paper is to review the influence of the operational conditions of xanthan production in the physiochemical characteristics of the gum produced.

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“…E. coli strains were grown at 37°C in LB medium, with ampicillin, kanamycin, or tetracycline when required (250, 50, or 15 ,ug/ml, respectively). (24,29) and of the depyruvylated xanthan gum produced by mutant strain 31313 (B) (32). From vol/vol/vol).…”

Section: Methodsmentioning

confidence: 99%

“…The wild-type X. campestris strain used was NRRL B-1459 (25). ATCC 31313 is a nitrosoguanidine X. campestris mutant that produces essentially pyruvate-free xanthan gum (32,35). A. xylinum PEA-1 is a cellulose-deficient mutant derived from the wild-type strain NRRL B-42 after mutagenesis with nitrosoguanidine.…”

Section: Methodsmentioning

confidence: 99%

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Location and cloning of the ketal pyruvate transferase gene of Xanthomonas campestris

et al. 1991

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Genes required for xanthan polysaccharide synthesis (xps) are clustered in a DNA region of 13.5 kb in the chromosome of Xanthomonas campestris. Plasmid pCHC3 containing a 12.4-kb insert of xps genes has been suggested to include a gene involved in the pyruvylation of xanthan gum (N.E. Harding, J.M. Cleary, D.K. Cabañas, I. G. Rosen, and K. S. Kang, J. Bacteriol. 169:2854-2861, 1987). An essential step toward understanding the biosynthesis of xanthan gum and to enable genetic manipulation of xanthan structure is the determination of the biochemical function encoded by the xps genes. On the basis of biochemical characterization of an X. campestris mutant which produces pyruvate-free xanthan gum, complementation studies, and heterologous expression, we have identified the gene coding for the ketal pyruvate transferase (kpt) enzyme. This gene was located on a 1.4-kb BamHI fragment of pCHC3 and cloned in the broad-host-range cloning vector pRK404. An X. campestris kpt mutant was constructed by mini-Mu(Tetr) mutagenesis of the cloned gene and then by recombination of the mutation into the chromosome of the wild-type strain.

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Influence of the pyruvate content of xanthan on macromolecular association in solution

Cited by 140 publications

References 16 publications

Development of a buccal mucoadhesive film for fast dissolution: mathematical rationale, production and physicochemical characterization

Development of a buccal mucoadhesive film for fast dissolution: mathematical rationale, production and physicochemical characterization

Goma Xantana: características e condições operacionais de produção

Location and cloning of the ketal pyruvate transferase gene of Xanthomonas campestris

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