Pre-Steaming, Soaking & Parboiling Unit is used to parboiling the rice. Pre-steaming is done due to shorter parboiling time. Parboiling is a hydrothermal treatment in which paddy is soaked in water and steamed to obtain gelatinized rice. Parboiling seals any cracks within the rice, causing the rice to become harder and resulting in a higher milling yield with less breakage.