Effects of Drying Temperature and Moisture Content on Rice Taste Quality

The influence of drying temperature on rice taste quality was studied in this paper. The heated-air temperature of 40℃, 45℃, 50℃, 55℃, and 60℃, respectively, were used to dry fresh paddy. The critical drying temperature of 45℃ for paddy rice with an initial moisture content of 21.36% w.b. was obtained, which induce the rice taste value declining significantly. Also, the amorphous starch matrix inside the rice kernel, which takes the shape of hardly dissolved starch granular, was observed by electron microscope. The fatty acid content of the rice increases as the drying temperature, which results in a higher degree of rice aging and restrains starch gelatinization during rice cooking. Those are key factors leading to the degradation of rice taste in the post-drying paddy. In order to preserve rice taste quality, a drying temperature below 45℃ is recommended for drying paddy, if its initial moisture content is less than 21.36%. The relationship between the major rice ingredients viz protein, amylose, moisture, and fat acid and taste value was established based on the experiment data used to predict rice taste quality.