Effect of Change in Cooling Rate on the Gelation of Sodium-type Gellan Gum

Abstract

The effects of change in cooling rate on the gelation of 0.8% sodium-type gellan gum solutions with and without 0.3% sodium chloride (NaCl) were investigated based on the storage moduli of the solutions. The cooling rate was changed at the temperature where the storage modulus began to increase. The storage modulus of 0.8% sodium-type gellan gum solution with 0.3% NaCl was larger in the measurement for cooling rate change from slow to fast than in that for change from fast to slow.
After the cooling rate change, in cases where the rate was equal to that before the change, the slower the rate, the larger the storage modulus. When the cooling rate was changed from slow to fast, the lower the temperature at which the rate was changed, the larger the storage modulus became. These results show that the cooling rate before the increase of storage modulus has a remarkably large influence on the formation of three-dimensional network structure.