Influence of Milling on the Vitamin and Mineral Content of Maize

G rm Rationale Maize or corn is a cereal with ears consisting of either white, yellow or rust coloured grains, rich in starch, which are attached to a cob protected by layers of fibrous leaves. The way in which maize is processed and consumed varies greatly from country to country, maize flour and maize meal being two of the most popular products. For maize meal, the whole grain is ground into a granulated meal with a range of particle sizes from coarse to fine, while maize flour is obtained from milling the endosperm of the maize grain after the germ and outer layers are removed (see Figure 1). These products have replaced whole maize as important components in the diet in many parts of the world. As with all cereals, most micronutrients are concentrated in the outer layers of the grain; thus removing these layers in the milling process results in the loss of most vitamins and minerals. These losses, however, can be replaced through enrichment or fortification without affecting the quality or acceptability of foods made from maize flour or maize meal. Maize flour or maize meal can be considered in fortification programs because they are staple foods in many parts of the world. For example, in Zambia, over two-thirds of the daily energy intake comes from maize; in Central America, almost one-half of the daily energy intake comes from maize flour; and in a number of other countries between 10 and 30 percent of daily energy intake is from maize flour or maize meal (Table 1).