Head purple rice yield
Fig. 4 showed the percentage of HPRY of the sample dried by fluidization technique at the initial moisture of 28.3 and 33.3% (db), drying temperature at 100-150oC wherein the result was found that the percentage of HPRY had the value in the range of 40.8-44.3% and 42.9-46.2%, respectively, while such percentage of the sample dried by sun drying method yielded the value at 41.1 and 40.6%.
When comparing the result of the analysis at the paddy initial moisture of 28.3% (db), HPRY of the purple rice dried under the temperature of 150oC had the percentage of HPRY higher than the sampling purple rice dried under the temperature of 100oC and the sample dried by sun drying method while at the paddy initial moisture of 33.3% (db), the percentage of HPRY had a trend of the higher increase when the drying temperature of over 100oC was used. The increase in the percentage of HPRY was derived as a result of the starch gelatinization during drying process. In process of starch gelatinization, starch granule and protein within the rice grain would take place on the reorganization of the structure; cracks within the rice grain which might occur during the harvesting process could be tightly joined eventually resulting in molecular structure to be strengthened; rice grains could resist the stress arising from the drying process including steadfastly enduring against the dehusking process better.[21] For such reason, the percentage of HPRY of the sample at the initial moisture of 33.3% (db), dried by hot air under the temperature of 130 and 150oC would therefore yield a high value because the degree of starch gelatinization under both of such 2 drying conditions was more than other drying conditions.