Industrial Process

The stages of industrial process transforming rough rice into eatable rice are:
• cleaning and hulling
• whitening and polishing and optical separation
• product packing

The rice transformation process starts with cleaning product from impurities as straw, mould, stones, foreign seeds etc; this operation is carried out by a proper machine called TARARA. Following stage is carried out by hulling machine that thanks to a chafing movement removes siliceous bracts (hull). After this operation we have brown or semi-milled rice. During this operation, rice grain can be easily broken, so care must be kept. Paddy machine follows: it separates the semi-milled rice grains from the ones that still have hull and makes them returning to the hulling machine.
This kind of rice is difficult to preserve, because grains still have pericarp and aleuronic layers whose lipoidal and proteinous elements present an high deterioration level. The only way to preserve this kind of rice is at low temperatures or vacuum. The semi-milled rice is then calibrated using proper-gauged sieves, which separate the sub-product known as green grain (immature grains and/or smaller grains) particularly used by zootechnics industry.
During hulling operation care must be taken not to break the rice. Whitening and polishing operation removes chaff, bud and rough flour by polishers that operate as follow:
• rice grains enter in a space between two concentric cones (the internal one is a rotary cone with an abrasive surface);
• thanks to a chafing movement, first and second layers (chaff and bud) are removed;
• further chafing operations remove also rough flour.
At the end of the polishing stage, it is necessary to separate the white rice from the broken grains by means of honeycomb separators.
Thanks to the optical separation, it is carried out a further rice refining by grains color: rice undergoes a series of color sensitive photo-cells which point out any grain with coloring different from the pre-set standard. A jet of compressed air is used to expel the selected grains. Coloring defects often occur during milling stages, for example heat causes peck phenomenon.
The last process stage is packing operation: 1 – 2 – 5-10-20 Kg plastic, paper or cloth bags are used. Automatic chargers fill up boxes and bags with fixed quantities of rice and then boxes and bags are sealed by sewing or heat seal.
Market now is requiring a product that does not present many preservation problems, so we have decided to supply vacuum packs. This packing system prevents product from every kind of oxidation, but weighs heavily on operation costs, because implies the use of thicker and absolutely airtight materials and relevant machines productivity is three times less than normal packing machines.