Abstract:
Paddy parboiling unit was fabricated to produce SriLankan quality standard parboiled rice
of two improved Sri-Lankan rice varieties: At 362, Bg 366 and one traditional rice variety
“Addakari” at different parboiling conditions such as duration of soaking (hours), and three
steaming methods: Pressurized-Soaking Steam (PSS), Un-soaked Steam (USS) and Soak
Steam (SS). Quality standards of parboiled paddy were investigated for head rice yield (HR)
during milling and resistance starch formation (RS) during cooking and texture during
extrusion, with raw paddy rice as a control. Results show that PSS recorded the highest
head rice yield as (90 ± 5%), which was achieved as a higher milling yield than the other
traditional steaming methods investigated, which achieved this for 2 days of soaking
duration (48 hours) and 30 minutes of steaming. All other compared steaming methods
(USS and SS) achieved a moderate head rice yield of 70 ± 5%. The cooked rice kernel had
high RS and a lower extrusion percentage (65 ±5%). Among the combined parameters
tested in this investigation traditional variety “Addakari” performed higher RS than the
improved paddy variety under the improved PSS streaming process with lower extrusion
outcome (75 ± 5%). Raw rice showed lower RS with higher extrusion output (90 ± 5%) and
lower milling recovery yield (65 ±5%) than all other parboiled rice samples investigated.
Findings reveal that traditional variety performed a higher quality standard of parboiled
rice than improved paddy variety.
