Viscoelastic properties of an exocellular polysaccharide produced by a Lactococcus lactis.
The viscoelastic properties of a well-characterized exocellular polysaccharide (EPS) produced by the lactic acid bacterium Lactococcus lactis subsp. cremoris strain B40 were investigated. Dynamic rheological measurements were made as a function of frequency and EPS concentration. The bead-spring model of Rouse could reasonably describe the dynamic properties. Concentrated EPS solutions have a significant elasticity (G' > G") at high frequencies. The relatively high G' values at high concentrations and high frequencies are indicative of significant normal stress differences, and we put forward a hypothesis that suggests that these normal stresses may explain the contribution of EPSs to the ropy behavior of yogurts.
Tuinier
R
R
NIZO Food Research, P.O. Box 20, 6710 BA Ede, The Netherlands. tuinier@nizo.nl or r.tuinier@chem.uu.nl
Oomen
C J
CJ
Zoon
P
P
Stuart
M A
MA
de Kruif
C G
CG
D000465:Algorithms; D004548:Elasticity; D017045:Lactococcus / Q000378:metabolism*; D008954:Models, Biological; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D013314:Stress, Mechanical; D014783:Viscosity
D011135:Polysaccharides, Bacterial