by
Hiromi Saita, Senior Staff, International Management Office, Satake
Corporation, Japan
Post-harvest conditioning and processing of rice and milling
As one may already be aware, rice just after being harvested is referred to as paddy. Paddy consists of four parts: husk (the brown part as seen in Figure 1), bran (the yellow part), germ (the purple part), and endosperm (the blue part). Rice conditioning/milling is a series of processes to extract the endosperm (the blue part), that people normally eat, by removing the other components without damage. The process generally refers to the following five stages.
1. Drying is a stage necessary for the stable long-term storage of rice. Rice harvested in the field contains more than 20 percent moisture by weight. If left in high temperature and humid environments, it will deteriorate in less than 24 hours. To prevent this, the rice is quickly dried after harvesting and the moisture level is lowered to around 15 percent. Hot/warm air is used for drying with careful temperature control, since the rice will be cracked or burnt if hot air is applied for too long.
2. Husking is a stage of removing husk (the brown part in Figure 1) from the dried paddy. Husk is a hard shell that protects both the germ and endosperm of the paddy. It is rich in fibre and silica, therefore making it unsuitable for people to eat.
In order to carry out the subsequent milling of rice with regard to high quality and high yield, first we remove the outer husk. A pair of rubber rolls rotating at high speed is used for rice husking. The two rubber rolls are rotating inwardly at differing speeds so that the husk is removed as the paddy passes between them. If the rubber roll spacing is too small, the rice may crack or the bran may scrape off, adversely affecting the subsequent rice milling. Rice after husking is referred to as brown rice.
3. Milling is a stage of removing the bran and germ which cover the brown rice, leaving only the endosperm. Several types of milling machinery are used to remove the bran gently to avoid damaging and/or breaking the endosperm. On a side note, a rinse-free rice is considered as an extension of rice milling. It is a rice processed to remove nearly all the bran on the surface of the grain, utilising tapioca.
Read more HERE.
Post-harvest conditioning and processing of rice and milling
As one may already be aware, rice just after being harvested is referred to as paddy. Paddy consists of four parts: husk (the brown part as seen in Figure 1), bran (the yellow part), germ (the purple part), and endosperm (the blue part). Rice conditioning/milling is a series of processes to extract the endosperm (the blue part), that people normally eat, by removing the other components without damage. The process generally refers to the following five stages.
1. Drying is a stage necessary for the stable long-term storage of rice. Rice harvested in the field contains more than 20 percent moisture by weight. If left in high temperature and humid environments, it will deteriorate in less than 24 hours. To prevent this, the rice is quickly dried after harvesting and the moisture level is lowered to around 15 percent. Hot/warm air is used for drying with careful temperature control, since the rice will be cracked or burnt if hot air is applied for too long.
2. Husking is a stage of removing husk (the brown part in Figure 1) from the dried paddy. Husk is a hard shell that protects both the germ and endosperm of the paddy. It is rich in fibre and silica, therefore making it unsuitable for people to eat.
In order to carry out the subsequent milling of rice with regard to high quality and high yield, first we remove the outer husk. A pair of rubber rolls rotating at high speed is used for rice husking. The two rubber rolls are rotating inwardly at differing speeds so that the husk is removed as the paddy passes between them. If the rubber roll spacing is too small, the rice may crack or the bran may scrape off, adversely affecting the subsequent rice milling. Rice after husking is referred to as brown rice.
3. Milling is a stage of removing the bran and germ which cover the brown rice, leaving only the endosperm. Several types of milling machinery are used to remove the bran gently to avoid damaging and/or breaking the endosperm. On a side note, a rinse-free rice is considered as an extension of rice milling. It is a rice processed to remove nearly all the bran on the surface of the grain, utilising tapioca.
Read more HERE.
The Global Miller
This blog is maintained by The Global Miller staff and is supported by the magazine Milling and Grain
which is published by Perendale Publishers Limited.
For additional daily news from milling around the world: global-milling.com
No comments:
Post a Comment