Parboiling is an ingenious technique for increasing the nutritional value of polished rices. It dates back many centuries and seems to have been developed in southern India. Many people in Bengal, Bangladesh, southern India, and Sri Lanka prefer parboiled rice.
Rice still in the hull is boiled, then cooled. This has the effect of driving vitamins from the bran into the center of the rice. The rice is then husked (the hulls are removed) and milled (which gives it better storage qualities—no germ or bran to go rancid). Though milled, it retains much of the nutritional value of unpolished (brown) rice.