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|Título:||Rheological characterization under shear of a fraction of polymer produced via fermentation of whey-related media by Rahnella aquatilis|
|Autor:||Pintado, M. E.|
Silva, J. A. Lopes da
Pintado, A. I. E.
Malcata, F. X.
|Citação:||PINTADO, M. E....[et al] - Rheological characterization under shear of a fraction of polymer produced via fermentation of whey-related media by Rahnella aquatilis. Carbohydrate Polymers. ISSN 0144–8617. Vol. 37 (1998), p. 1–6|
|Resumo:||Production of lactan, a polysaccharide composed of mannose, galactose and galacturonic acid (at the ratio of 5:3:2), starting from a semidefined medium containing lactose via fermentation with Rahnella aquatilis was described previously. In this communication, such polysaccharide was produced from five alternative fermentation media: (1) a synthetic (defined) medium, plain whey (under (2) aerobic and (3) anaerobic conditions), (4) whey permeate and (5) whey with 2% NaCl (w/v). The effect of the concentration of polysaccharide, pH and ionic strength at harvest on the rheological properties of the polysaccharide was studied using lactan-enriched fractions recovered from each medium and analysed in solution under steady shear flow. Lactan solutions showed a shear-thinning behaviour in all cases, and increases in viscosity were observed at increasing concentrations of polysaccharide, as expected. The polysaccharide fraction produced from whey with 2% (w/v) NaCl and plain whey under anaerobic conditions exhibited lower viscosity than that produced from the other media, an observation that is associated with the lower concentration of polysaccharide. Post-harvest addition of salts (KCl or CaCl2) and changes in pH (3–11) affected slightly the viscosity of the polysaccharide solutions. q1998|
|Versão do Editor:||http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFD-3VKBPB0-1&_user=2460358&_coverDate=09%2F30%2F1998&_rdoc=1&_fmt=high&_orig=gateway&_origin=gateway&_sort=d&_docanchor=&view=c&_searchStrId=1749893649&_rerunOrigin=google&_acct=C000057417&_version=1&_urlVersion=0&_userid=2460358&md5=08ac895b2c4f6a52913b6a1d71704115&searchtype=a|
|Aparece nas colecções:||ESB - Artigos em revistas internacionais com Arbitragem / Papers in international journals with Peer-review|
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