Evaluating the Drying Characteristics of Paddy Rice Using Superheated Steam Dryer

Abstract It has been recorded in literature that superheated steam has the ability to combine the parboiling operation (steaming and drying) of paddy (Oryza sativa - UPL1) rice into a single unit. According to literature, this process has not been fully explored and implemented in rice processing. In this research work, superheated steam dryer was used to parboil (steam and dry) paddy rice. Soaking time and temperature used was 12hours at 60°C, with steaming time ranging from 10 to 24mins, while the drying conditions used were; temperature (160, 170 and 180°C), bed depth (1, 3 and 5cm) and tempering time (20 and 40 minutes). In addition, paddy rice was dried from initial moisture content ranging from 26-43% (d.b) to a final moisture content of 2 – 8% (d.b). It was observed that the milled rice yield ranged from 71.32 to 94.5%, head rice yield ranged from 70.5 and 90.6%, broken rice ranged from 3.2 to 7.7%, chalkiness ranged from 3.4 to 10.6% and drying capacity ranged from 0.1 to 0.36kg/h. The results obtained shows that drying with superheated steam can be used to improve rice quality.