Raw rice (paddy)
is the name given to the grains after the first processing stage - the threshing and drying stage - but when they are still blanketed in the tough husk, which also contains silicic acid. The grain is capable of germinating in this form, and can be used as seed. But it is not yet of any use in the kitchen.
Half raw rice
is familiar to consumers under the name ‘whole-grain rice’. The grain, consisting of rice starch and seed embryo, is now held together only by the nutritionally valuable bran and germ layer. The husks have been removed in rice mills in the producing country. These husks are often burned to produce energy. Brown rice, as already mentioned, is often known as cargo rice. With the husk removed, the rice takes up less volume and can thus be transported more economically.
is the product gained when whole-grain rice or brown rice is processed further. Having been purified from all foreign bodies, and sorted according to length and width etc, the bran and germ layer is filed away. This ‘wastage’ dust can itself be further processed to give the nutritionally valuable rice starch, used for example in the fodder industry. Rice-seed oil, a delicate, high quality house-hold oil, can be gained from the seed embryo. Where the last traces of dust have been cleaned off the rice, the resulting product is referred to as "polished rice".
From the silo train wagons, the semi-raw rice is then brought to the silos where it is temporarily stored before being further processed. The start weight is electronically calculated and the rice projected via air pressure into the first purification site. A system of layered sieves with holes of varying size are shaken to free the rice of foreign bodies, small stones etc, as well as sorting out broken rice grains. Dust and particles of husk remains are whirled up by air pressure and sucked away. Rotating drums with wire mesh then separate the ripe grain from the unripe (green grains).
The grains of rice are now moved on to the grinding machine, where a rotating grinding cone hurls the rice against the gritty inside wall. The grains fall slowly between the wall and the grinding cone, where they are brought to a halt by rubber braking pads 1 - 2 mm away from the cone. The different speed between the grinder and the grains produces the friction necessary for filing away the bran and germ layer. The nutritionally valuable grinding dust is sucked up and filled into sacks.
Once they have been sanded, the grains of rice move on to a further sorting process in a " "trieur" drum. The inside of this drum boasts countless small indentations in which broken grains stick, whilst the whole grains, remaining on the surface, can be raked off.
The rice is then passed through a colour sorting machine, where photographic cells instantaneously recognise off-colour grains, and sort these out by means of well-aimed blasts of air.
Finally, the rice - either in silos or filled into sacks - is stored, a large proportion of the storage being legally required. After roughly eight months, it is polished again, sorted again and packaged ready for sale. At the same time, the silos are filled again with the new harvest of processed rice.
Parboiled rice has almost the same nutritional value as whole-grain rice. Parboiling is a process used world-wide, generally with ultra-modern technology. The diagrams and descriptions below show a simplified version of the process. Parboiling is used on raw rice (paddy), which is then taken on to the rice mills and de-husked and further refined in the usual manner. In old times, a reduced version of this "parboiling" effect was achieved by steaming the raw rice and then drying it in the sun. Parboiled rice has a faint yellow gleam, but turns snow white during cooking, and retains its texture even when cooked for a long time.
Raw rice grains (paddy)
An enlarged excerpt depicting symbolically the vitamins and minerals contained in the bran and germ layer.
The parboiling process functions thus:A vacuum is created, removing all air from the raw rice. Soaked in tepid water, the vitamins and minerals in the bran and germ layer dissolve.
Steam and high pressure then force the water-soluble nutrients back into the heart of the grain of rice.
A second burst of hot steam hardens the starchy surface layer of the rice. This seal ensures that the nutrients remain inside the grain. Lastly, the grain is dried. Parboiled riceParboiled rice.