Abstract
This study reports on the reduction of moisture absorption of amorphous rice flour formed by ball milling. Ball milling has been applied to starch for conversion of its physico-chemical properties. Ball milling converts the semi-crystalline state of starch to an amorphous state, and the prolonged procedure promotes enthalpy relaxation. It has been reported that prolonged treatment leads to an decrease in starch water sorption. However, because the size of the ball mill container was small in a previous study, it was not suited for industrial applications. In the present study, a vibrated type ball milling with a large container of rice was carried out for up to 9hr. The confirmation of crystalline was evaluated by using the X-ray diffractometry. The relaxed enthalpy (ΔH) was measured by differential scanning calorimetry. Water sorption isotherms were measured by equilibrium sorption of water vapor. With the milling time, enthalpy relaxation was found to increase and water sorption to decrease. The sorption isotherms were analyzed with a dual mode sorption model, and the concentration, C’H, of Langmuir type sorption site was found to decrease with the time. In the present study, the ball milling was to improve the adsorption properties of rice flour, that regardless of the size of the ball mill container, it has been found that it is possible to create an amorphous rice flour with physicochemical properties.
