Thermal property of purple rice
Table 3 showed the thermal property of the referenced sample and dried sample under different drying methods and conditions. The data showed the transitional temperatures (To, Tp and Tc) delta enthalpy ( H) and degree of starch gelatinization (DG) which, in this respect, the experiment of such rice variety was found to be under the transitional temperature in the range from 66.0-77.5oC with the value of delta enthalpy of 9.91 J/g. From the consequence of the degree of starch gelatinization according to the Table 3, the drying process by sun drying method did not make starch in the rice grain to generate process of gelatinization.
At the initial moisture of 28.3% (db), even if the purple rice would be dried by the method of fluidization technique at the temperature of 100oC which the value of such temperature was higher than the gelatinization temperature at 66.0oC, but, with a short drying time, it would result in the end temperature of the grain at the moisture 22.0% (db) to be valued at only 60oC which was even lower than the gelatinization temperature. Therefore, under such drying condition, it would not result in the starch to be gelatinized. Where degree of starch gelatinization of the sample passed through drying process by fluidization technique under the other conditions had a trend of increasing in accordance with the increase in the paddy initial moisture content and drying temperature which the highest value was at 29.2% when the purple rice at the initial moisture of 33.3% (db) was dried under the temperature of 150oC.[38]