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Orientador(es)
Resumo(s)
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
Descrição
Palavras-chave
Lactan Rahnella aquatilis Polysaccharide
Contexto Educativo
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
Editora
Elsevier