Title of article :
Rheological characterization of exopolysaccharides produced by two strains of Streptococcus thermophilus
Author/Authors :
Purwandari, U. Victoria University, Werribee Campus - Faculty of Health, Engineering and Science - School of Biomedical and Health Sciences, Australia , Vasiljevic, T. Victoria University, Werribee Campus - Faculty of Health, Engineering and Science - School of Biomedical and Health Sciences - Institute for Sustainability and Innovation, Australia
Abstract :
Two strains of Streptococcus thermophilus producing capsular and capsular-ropy exopolysaccharides(EPS) were cultivated in M17 medium supplemented with lactose at 37°C for 24 hours. At the end of fermentation, EPS were extracted and their flow behavior was assessed as a function of concentration, pH and temperature. Apparent viscosity of capsular EPS dispersions was higher than that of the capsular-ropy EPS, while activation energy was lower. A pH increase amplified activation energy in both types of EPS. Flow behavior of both EPS dispersions was fitted well by the Cross model, with capsular-ropy EPS showing greater zero shear rate viscosity, relaxation time and limiting slope. These parameters were greatly affected by the strain type, pH and temperature.
Keywords :
Streptococcus thermophilus , exopolysaccharides , growth conditions , rheological properties
Journal title :
International Food Research Journal
Journal title :
International Food Research Journal
