1999 Volume 5 Issue 2 Pages 183-187
The effect of sucrose on water activity, the fraction of freezable water, and viscoelastic properties of alginate dispersed aqueous systems was investigated. Water activity and the fraction of freezable water were almost independent of the examined alginate concentration but decreased with increasing sucrose concentration, indicating that colligative properties of those systems were mainly determined by the sucrose content. The specific viscosity values were represented by a single master curve for all the systems containing a concentration of alginate lower than 0.5%(w/w). For the systems containing a concentration of alginate higher than 0.5%(w/w), the ratio of the loss modulus, G", to the storage modulus, G'; G"/G' (=tan δ) was almost independent of alginate concentration in the systems without sucrose, but the G"/G' values decreased with increasing alginate concentration in the systems containing sucrose. These results suggest that interactions between sucrose and alginate were negligible at a low alginate concentration, but that the elastic nature of the systems was enhanced due to sucrose-alginate interactions at a high alginate concentration.
