separated to ensure longer shelf life of the flour. In contrast to enriched flour, whole wheat flour contains both the bran and the germ. The remaining and largest portion of the seed is the endosperm. It acts as a nutrient reservoir for the developing embryo. The endosperm contains a large amount of carbohydrates, protein, iron, B vitamins (niacin and riboflavin), and soluble fiber. Once the endosperm is isolated, it is ground into a fine powder and sifted to remove any remaining fragments of bran or germ. Next, a chemical bleaching process is used to give the flour a whiter color. This bleaching step, usually with chlorine or benzoyl peroxide, destroys many of the original nutrients that were present in the flour. The final flour product contains a smaller portion of the original nutrients that were present in the seed prior to processing. Enrichment ensures that these important nutrients are restored to improve the quality of the flour. Enrichment requirements According to the U.S. FDA, a pound of enriched flour must have the following quantities of nutrients to qualify: 2.9 milligrams of thiamin, 1.8 milligrams of riboflavin, 24 milligrams of niacin, 0.7 milligrams of folic acid, and 20 milligrams of iron. The first four nutrients are B vitamins. Calcium also may be added; this must be to a minimum level of 960 milligrams per pound if calcium is mentioned in the labeling. Similar rules are set for grains like rice and maize. Other countries also have flour enrichment programs. See also Iodised salt – which might be called "Fortified salt". Whole-wheat flour References Flour