Rice is a staple food consumed heavily in every part of Nigeria. Rice merchants parades the production areas to buy rice in bulk for processing. The harvested rice from the farm is threshed and dried. At this stage it is called paddy rice. Paddy rice bought from the farm should be dry less than 18% moisture content. The next step is to parboil the rice.
Parboiling as the name of the operation implies is partial boiling of the rice. It serves two purposes.
A) to weaken the rice hull. Hull is the hard coat of the paddy rice and ease hulling.
B) To toughen the rice in order to reduce breakage during hulling.
Parboiling is better done by steam heating but most local farmers prefer total drenching and boiling. This also yield good result but drying takes longer time. Some farmers will even soak the rice overnight before parboiling.
Step 1: Put the container on the fire place . The container for parboiling is usually drum and the fire place made of three big stones or vehicle wheel rim of reasonable size. Set the drum on it and fill the drum up to 40 liters of water. Fill the drum with paddy rice almost to the brim.
Cover the drum with sac usually jute sac to conserve the vapor within the boiling chamber. Fire seriously until vapour start to escape from the top. When the hull of the rice on top start to open to reveal the rice inside then parboiling is done. That the rice is almost half done.
Step 2: Drain the excess water remove the rice and sundry. Dry to about 18% moisture level. It should not be too dry else there will be breakage during hulling. After drying pack the parboiled rice sac and carry to the mill.
Step 3: Milling is done by rice milling machine. There are locally made and imported rice milling machine. The rice milling machine consist of two chambers,. The first one is the huller. This chamber removes the rice hull. When the hull is removed the rice becomes brown rice. Brown rice is passed to the next chamber to polish. Polishing is the removal of the outer layer of the brown rice. This layer is also called bran.
After the bran has been removed the rice is now called polished rice. Polished rice is suppose to be coated with protein material to become coated rice like the imported rice but we do not bother about this in Nigeria. What we take to the market is the polished rice.
The rice hull removed is good feed for ruminant farm animals like cattle sheep and goat. The rice bran is very rich in protein and good and expensive ingredient for farm animals like pig and poultry feed.
It is very important that extra care should be taken not to contaminate the rice with stones, sand or any extraneous material at any stage of processing. This is where the difference lies between imported rice and local rice. The imported rice is free of contamination.