THESIS

Figure 1 A detailed structure of the rice grain
Source: Blakeney (1984)
Rice starch production involves mainly wet milling of broken with 0.3 -
0.5% sodium hydroxide to remove protein (Juliano, 1984). Broken are steeped in
alkali solution for 24 hours and are then wet milled in pin mills, hammer mills or
stone-mill disintegrators with the alkali solution. After the batter is stored for 10 to 24
hours, fiber (cell wall) is removed by passing it through screens; the starch is
collected by centrifugation, washed thoroughly with water and dried. Protein in the
effluent may be recovered by neutralization and the precipitated protein used as a feed
supplement. Rice starch is used exclusively as a human food, largely for baby foods
and also in extruded noodles.
2.2 Granule structure of rice Starch
The endosperm, the starchy inner portion of rice kernel, is composed of
tightly packed compound starch granules with protein interspersed as spherical bodies
and crystalline structures. The starch content is particularly high, up to 77.6 % in
16