Effect of Temperature and Starch Concentration on the Intrinsic Viscosity and Critical Concentration of Sago Starch (Metroxylon sagu)

Intrinsic viscosity and critical concentration of sago starch dispersions were studied at different temperatures and presence of solutes (sodium chloride, glucose and sucrose). Ubbelohde capillary viscometer was used to measure relative viscosity. Intrinsic viscosity decreases with an increase in temperature but the critical concentration remained fairly constant over the range of temperature studied. Sodium chloride enhanced the intrinsic viscosity but sugars somehow reduced it. Critical concentration is defined as the point where the starch molecules start to entangle with each other and abruptly enhance viscosity. Sodium chloride enhanced the molecular entanglement and lowered the critical concentration.