Relationship Between Degree of Starch Gelatinization and Quality Attributes of Parboiled Rice During Steaming

Paddy rice samples were parboiled by soaking at 65 degrees C for 180 min and steaming at 96 degrees C for 2-10 min, and then dried to achieve the final moisture content of 11% +/- 1%. The degree of starch gelatinization (DSG) and several quality attributes (head rice yield (HRY), color value and hardness) of parboiled rice were measured. Results showed that DSG (46.8%-77.9%), color value (18.08-19.04) and hardness (118.6-219.2 N) all increased following steaming. In contrast, the HRY increased (64.8%-67.1%) for steaming times between 2-4 min but decreased (67.1%-65.0%) for steaming times between 4-10 min. Linear relations between DSG and color value (R-2 = 0.87), and DSG and hardness (R-2 = 0.88) were observed. The suitable DSG of parboiled rice leading to the highest HRY was found to be 62.5%, obtained following 4 min of steaming.