Effect of Physical Aging on Physical Properties of Pregelatinized Tapioca Starch

The effect of physical aging on the properties of starch is important to understand structural relaxation and to control the physicochemical changes after pregelatinization which induced by aging. In this study, the effect of physical aging on the physicochemical properties of pregelatinized tapioca starch was investigated. The tapioca starch was pregelatinized by either heating at 80°C or using high power (400 W) ultrasonic treatment. After pregelatinization, dextrose equivalent (DE), viscosity, turbidity, swelling power and solubility were determined and compared with native tapioca starch. Compared to fresh tapioca starch, the aged starch exhibited an increase in DE, turbidity and solubility. The viscosity and swelling power were decreased after storage. Similar results were found for both tapioca starches pregelatinized by heat and ultrasonic treatments. The results of the physicochemical properties of pregelatinized starches obtained from ultrasonic treatment related to the formation of low molecular weight components that aging starch are easily changed by disruption of molecular structure within the starch granule.