Quality Standard Improvement of Traditional Paddy Parboiling Processin Northern Sri Lanka

Abstract

Parboiled rice (Brown-rice) exhibits several advantages over raw rice (Red-rice), such as, increased milling recovery, strengthening kernel integrity by forming resistant starch with preventing the loss of nutrients during cooking and improve the Glycemic Index. In this study to investigates the three key stages of parboiling process as soaking, steaming, and drying at small scale for the improvements by the different hydrothermal treatment combinations such as duration of soaking in days, and methods of steaming as closed steaming as Pressurized-Soaking Steam (PSS), semi open as Un-soaked Steam (USS) and Soak Steam (SS) as open steaming. rice quality standard through milling yield and cooking quality standards, which refer as Head Rice Yield (HR) during milling and resistance starch formation (RS) after cooking. Paddy varieties, of Ambalanthota rice (At 362), Bathalagoda rice (Bg 366) and one traditional rice variety “Adakari” were selected. Closed streaming (PSS) for 30 minutes of steaming duration and 2 days of soaking duration (48 hrs.) was recorded higher milling recovery as highest head rice yield (80 ± 5%) in milling analysis. Traditional steaming methods semi-open and open (USS and SS) achieved moderate levels of head rice yield 70 ± 5% at same soaking level in all three varieties. There was a significant different between soaking duration and steaming methods at (p < .005) level and there was no significant difference in between variety (p = 0.759). Raw paddy (Non soaked and non-steam) as control. Texture investigation of further improvement in parboiled rice cooked, which was performed by texture analyzer. Radiational rice variety (Adakari) performed better in the formation of resistant starch under the closed steam (PSS) processing condition which was yield a higher texture compression as 10-12 Newton force than other improved paddy varieties tested. Non- parboiled sample (control) was yielding a lower level of head rice 60 ± 5% and low texture analyser compression 6-7 Newton force in all three varieties. Therefore, practice of closed steaming method (PSS) in parboiling was performed better quality standard parboiled rice with good texture after cooking, which improve the quality standard traditional parboiling processes in northern Sri Lanka.