Abstract:
Parboiled rice exhibits several advantages over raw rice, such as strengthening kernel
integrity by forming resistant starch, increased milling recovery and preventing the
loss of nutrients during cooking and improve the Glycemic Index in digestibility.
Recommended paddy varieties tested with red pericarp (At 362), red pericarp (Bg
366) and one commercially available red pericarp (Adakari). The main objective of this
study is to investigate the effect of soaking duration and steaming method on milling
yield and resistant starch formation during cooking of parboiled rice. Soaking was
done in cold water (30 °C) for different time duration ( a day, 2 days, 3 days, 4 days,
and 5 days) with a volume ratio of 1:1.5 and the steaming (boiling) was practiced for
20 minutes’ duration as Pressurized Soak Steam as closed steam (PSS), Un-soaked
Steam as semi open steam (USS), Soak Steam as open steam (SS), in an electric steam
rice cooker with steamer. The parboiled paddy was dried under a conventional oven
at 60 °C temperature for 3 hrs for safe milling. Head Rice Yield (HR), Broken rice yield,
milling recovery, and texture hardness of parboiled rice were evaluated. Statistical
analysis showed a significant interaction between soaking interval and steaming
methods (p < .005). 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 and resistance starch
(RS) formation during cooking was investigated by texture analyzer under Trigger
Force of 0.05 N (auto). Results showed that the higher head rice yield was counted in
the closed pressure steam (PSS) method with 2 days of cold soaking duration (48 hrs).
Closed pressure steam (PSS) resulting formation of harder resistant starch parboiled
rice during texture analyzing than other treatment methods investigated. Open and
semi open parboiling treatments gave moderate head rice yield and hardness texture
value. Closed pressure steaming parboiling (PSS) process was yield the high hardness
texture value and improved yield product.
