A laboratory-scale experimental setup was fabricated to produce parboiled rice at lower temperatures (80, 90 and 100°C) to determine cooking qualities for different processing conditions and sample sizes (75, 120, 200 and 400g). The cooking qualities, such as water uptake value, solid content in the cooking gruel and cooking time of parboiled rice, were investigated. The cooking time of parboiled rice can be determined at the water uptake value of 2.5. The water uptake value and solid content decreased, and cooking time of parboiled rice increased according to the severity of the heat treatment in the parboiling process. A good linear relationship between the thermal property and cooking time clarified the cooking behavior of parboiled rice. A cooking time of 20 to 24min was obtained for the improved quality of parboiled rice produced at the processing conditions of 90°C-30min and 100°C-10min. It was assumed that for the respective cooking time, cooked under identical conditions, all parboiled rice might show the distinct level of solid contents.