Processing conditions and milling yield in parboiling of rice.

Rate of absorption of water by paddy (rough rice) increases with. the temperature, but is
relatively low below the gelatinization point; beyond this point, the grain absorbs water
rapidly, preferentially on its surface layers, leading to early bursting and leaching. Hence
for best efficiency, soaking for parboiling should be done slightly below the gelatinization
point, or, more conveniently, by storting at 70° to 75° C. and allowing natural cooling.
Milling quality of parboiled paddy depends on severity of heat treatment during parboil·
ing and conditions of drying; the more severe the heat treatment, the better it is able to
withstand adverse drying. Insufficient sooking leads to increased breakage. Simple
soaking of paddy at or above 70 0 C. also improves milling quality. Rate of hydration
of paddy as well as improvement in its milling yield by parboiling shows varietal difference.