Why is flour bleached?
When flour is first milled it has a yellowish tinge that consumers generally find unappealing. If the flour is stored and allowed to age naturally for several months, the color will fade. However, most flour producers find that storing large amounts of flour for long periods of time is too expensive. Instead, they choose to whiten their flour with a chemical bleaching agent such as benzoyl peroxide. Other agents that artificially age the flour are added as well, since mature flour produces better baking results and has a longer shelf life than newly milled flour. Because the bleaching process causes some nutrients to be lost, U.S. law requires that the flour be enriched—meaning that nutrients are returned to the flour. Source: Feldman, David. When Do Fish Sleep? And Other Imponderables of Everyday Life, pp. 63-64.
