Rheological characterization under shear of a fraction of polymer produced via fermentation of whey-related media by Rahnella aquatilis

• Type: Article in International Scientific Journal
• Date: 1998

Authors

Pintado, ME (Author) Other; da Silva, JAL (Author) Other; Pintado, AIE (Author) Other; F. Xavier Malcata (Author) Other

Journal

Title: Carbohydrate Polymers

Vol. 37

Pages: 1-6

ISSN: 0144-8617

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 5 Citations

Scopus - 7 Citations

Other information

Authenticus ID: P-001-74Q

DOI: 10.1016/s0144-8617(98)00032-0

Abstract (EN): 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6