Role of exopolysaccharides produced by Lactococcus lactis subsp cremoris on the viscosity of fermented milks

Lactic acid bacteria strains that produce exopolysaccharide (EPS) are employed in the manufacture of fermented milk to improve its texture and viscosity. No clear correlation has been found between EPS concentration and the viscosity of the fermented milk. It is supposed that the molecular characteristics, i.e. radius of gyration and molar mass, of these biopolymers play a part. The subject of this study was to clarify whether the viscosifying properties of EPS in aqueous solution can be related to the viscosity of fermented milk products. Therefore, we aimed at relating the molecular characteristics of EPSs produced by several strains of Lactococcus lactis subsp. cremoris in milk at three incubation temperatures to the viscosity of the fermented products. For a given EPS concentration, a positive correlation between the EPS-viscosifying parameters (intrinsic viscosity, Kuhn segments length and thickening efficiency) and the Posthumus viscosity of fermented milks was found. (C) 2002 Elsevier Science Ltd. All rights reserved.