A vast majority of the people in the
world consume rice. It is the second most important cereal in the world today
and provides together with wheat, a large proportion (95%) of the total
nourishment of the world’s population. It is the daily food for over 1.5
billion people (Juliano, 1993) because it is easily digested.
Juliano (1993) found that rice is an
essential food in the diet of one third of the world’s population and further
stated rice production and consumption is concentrated in Asia where more than
90% of the world’s rice is grown and consumed. The 155 million hectares planted
throughout the world produce about 596.5 million metric tons of paddy rice per
year (Li, 2003).
Rice, which is grown under a wild
diversity of climates, soils and production systems, is subjected to many
biotic and a biotic stresses that vary according to site. Consumption per
capital and consumer preferences for a given rice type also vary from region to
region (Juliano, 1993).
The annual demand for rice in the
sub- region is estimated at over 8 million metric tons. Rapid population growth
(estimated at 2.6% per annum), increasing urbanization and the relative ease of
preservation and cooking have influenced the growing trend in rice consumption.
Since the 1970s, production of rice has been expanding at the rate of 5.1% per
annum, with 70% of the growth due to increase area cultivated to rice, and only
30% due to higher yields, per unit area (anon, 2008a). Currently, an estimated
4.4 million hectares are under rice cultivation in West African (Somado et al., 2008). Total rice paddy
production in the sub region estimated to be about 6-2 million metric tons
(Anon, 2008b).
Berisavljevic
et al. (2003) reported that rice is
important to Ghana’s economy and agriculture, accounting for nearly 15% of the
Gross Domestic product. This sector of agriculture provides employment for a
lot of rural dwellers. Due to the shift in the diet of Ghanaians to rice
consumption, particularly those in the urban areas, imports of rice have been
increasing steadily since the 1980s. Imported rice is estimated to account for
more than 50% of all rice consumed in the country (Berisavljevic et al; 2003).
The increase in demand for imported rice is primarily attributed to increased
income, good storability and ease of cooking (Shabbir et al; 2008).
BY-PRODUCT UTILIZATION
Rice
hulls, bran and germ are used as animal feed. The hulls can also be used in
making mats, hats, roofs, and fuelling dryers. Commercially the hulls can be
used to manufacture furfural while rice bran oil which is recovered by the
solvent extraction process is used for cooking, in soap manufacture and as
seasoning for salads.
Rice hulls yield about 22% of ash,
of which 95% is silica and most of the remainder, lime and potash.
Consequently, rice hull ash has cementing properties and can be used in
construction as mortarn. The manufacture of brewed and distilled spirits also
utilizes rice in some areas.