Abstract:
The parboiling process leads improves rice quality and enhances the physio-chemical
properties of grains. Parboiled rice exhibits several advantages over raw rice products,
such as strengthening kernel integrity by forming resistant starch, increased milling
recovery and preventing the loss of nutrients. Two Department recommended
varieties with red pericarp (At362), white pericarp (Bg366) and one industrial type
with red pericarp (Adakari) were used for investigation in this study. Paddy samples
were prepared in different duration and methods of soaking and steaming with
controls (Raw rice). Different parboiling practices were investigated on their milling
yield qualities, refers as Head Rice Yield (HR) and resistance starch formation (RS)
during cooking. Initially, raw paddy samples were soaked in cold water at the intervals
of a day, 2 days, 3 days, 4 days, and 5 days with a volume ratio of 1:1.5 and the
steaming procedure was practiced for 20 minutes duration as Soak Steam (SS),
Pressurized Soak Steam (PSS), Un-soaked Steam (USS) in an electric rice cooker with
steamer. The parboiled paddy was dried under a conventional oven at 60 ˚C
temperature for 3 hrs., which achieved a suitable moisture level for safe milling. An
extrusion test was performed to test the internal strength of the rice kernel after
cooking. Cooking of Parboiled rice was performed with water in a volume ratio of
1:1.2, duration of 20 minutes in an electric rice cooker. The running temperature of
the extruder was 30 ˚C, and the speed was 30 rpm. There was a rice kernel had high
resistant starch content extrusion test yield outcome is low. The Highest head rice
yield was counted in the Pressure-soaked steam (PSSP) method with 2 days of soaking
duration (48 hrs). Pressure-soaked steam (PSS) samples show a lower extrusion
outcome than other parboiling methods, yielding good resistant starch parboiled rice.
All other parboiling methods gave moderate head rice yield and extrusion outcome.
Raw rice samples show a higher extrusion outcome and lower resistant starch than
parboiled rice samples.
