Bradbrook - 2012 - Rice Farming complete with methods to increase ric

Section 4: Post-harvest Processing
Rice terminology
Paddy or rough rice is the term used for rice grains that have just been harvested and still have
their husks (hull) intact. Brown rice is the term used for rice grains whose husks have been
removed but which still have the bran layer intact. The bran layer is rich in in dietary fiber,
vitamins, and minerals, but it also has a high fat content. This means brown rice, although
more nutritious, has a shorter shelf life than rice in which the bran layer has been removed.
Removing the bran layer reveals the white endosperm, which is called white or milled rice.
Consumers have a preference for white rice, even though it is low in nutrients. In countries
such as the United States, white rice is coated with vitamins and minerals to make it more
nutritious. But in many poor countries where rice is eaten as a staple food, nutrient
supplementation of rice is not a wide practice, so rice producers are encouraged by the
governments to leave a bit of the bran layer during milling.
Part 17: Drying
Drying is the most critical post-harvest operation in rice production. It is the process
of reducing the moisture content in rough rice to a level that is safe for storage. Drying
removes moisture that can encourage the growth of molds, cause discoloration, and
decrease the grain quality. Harvested grains should be dried within 24 hours. There
are many methods of drying and there is not one specific method that is recommended
for all drying operations in rice. There are drying methods for small-scale and largescale
operations. It is helpful to obtain a moisture meter to detect the moisture content
of the grains as they dry. The moisture content determines how long grains can be
safely stored.
Length of storage
Required
Moisture
Content
Possible problems
2 weeks to a few months 14 to 18% molds, discoloration, respiration loss,
insect damage
8 to 12 months 13% loss of germination
>1 year 9% loss of germination
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