For restoration of vitamins and mineral
cost during milling, the enrichment of rice is important for
better nutrition. There are two major
approaches. Powder enrichment and coated kernel enrichment. For preblended
powder enrichment, mixes includes, thiamins riboflavins, niacin, niacinamind,
ferric orthophosphate (white iron) ferrous sulphate (yellow iron) or reduced
iron which is relatively water insoluble
and white in colour (Hffpaur 1992). This is an easy and less
expensive approaches for enrichment
of rice. But the disadvantages of
the powder
enrichment are that the
nutrient are easily washed off by rinsing, less stability of vitamins, and
minerals and their reaction with
the food component. An alternative
approach is the coated kernel
enrichement this method integrates the powder
blended enrichment with insoluble
food grads coating. This coating is
broken down and the enriched vitamins
and minerals. After enrichment, the nutrient
levels are the same as those of brown
rice. The multi nutrient enriched rice is blended with rice at ratio of
1:200 only 10percent of any nutrient is lost through ordinary washing before cooking and
another 10 percent on cooking
Juliano (1993) . The pioneering enrichment field studies in Bothan province, the Philippines in
1948-50 demonstrated that rice
enrichment was practical, with sticking
reduction in the incidence of beriberi in the area in which enrichment was used Saledo et al,
(1950), Williams, (1956).
Moreso, a simple procedure has been developed to fortify rice with calcium Lec et al (1995).
It consist of infusing calcium
salt into the rice grain through
controlled steaming technology, the fortification process met the united
state standard. calcium fortified rice,
110-22mg/100g and resulted in mineral
washing losses of calcium.
Obstacles to the successful introduction
of rice enrichment by premix
method includes the following
-
The cost of
the imported premix
-
The difficulty of ensuring that the premix is
added to rice in correct proportion in the mill.
-
The
slightly greater cost of enriched rice
as compared with that of ordinary
rice, which affects its sales to lower
income groups.
-
Loss
of added vitamins, which may occur when enriched rice is cooked in excess water that is
subsequently discarded according
to current practice in some
rice eating countries.
-
Issues
related to standards and analysis, part
insularly of imported
rice.
-
Lack
of knowledge about the lose
of added nutrients during storage FAO (1854).
Under-milling has been employed to
retain B vitamins in milled rice, but
the shift-life of under-milled rice is
shorter than that of milled rice and the product is less white (FAO 1954). Some
consumers re-milled the under –milled rice to remove the rancid outer layer and to make the rice white, with an
accompanying lost of B vitamins. Of B vitamins. Mille rice has
also been used for enrichment programmes for vitamin A as
well as B vitamins in Thailand
and Philippines FAO (1954).
Figure 1. Flow chart of Rice processes
Whole grain rice
Cleaning
Hulling
Sieving /Aspiration
Brown rice
Pearling /Milling
Aspiration
White rice
Polishing
Packaging
Packaged rice
Source:
Okaka 1997