Effect of presoaking on cooking time and texture of raw and parboiled rice.

Milled raw rice ('IR 20', 2 yr old) needed about 15 min to cook in excess boiling water. Parboiled rice (normal-, pressure-, roasted-parboiled) required longer (21-32 min) depending on parboiling conditions. Cooked parboiled rice was shorter (2-10%) in length, but thicker (15-20%), firmer (about 5%) and considerably more elastic (15-20%) than cooked raw rice. Presoaking at room temp. for 15 min and 2-3 h for raw and parboiled rice, resp., reduced cooking time by 50 and 25-40% for raw and parboiled rice, resp., as compared to unsoaked controls. Presoaking raw rice resulted in an increase in length (about 20%) of cooked raw rice but a reduction in thickness (about 5%), firmness (about 10%) and elasticity (about 25%) as compared to unsoaked cooked control. Presoaking of parboiled rice did not significantly change these parameters.