Unbleached Wheat Flour
Also Known as Unbleached or Enriched Wheat Flour
What is Unbleached Wheat Flour?
Unbleached wheat flour is wheat flour not treated by bleaching chemicals. Wheat flour has the bran and germ removed, leaving only the starchy endosperm. It is made from grinding the wheat kernel.
Originally milled wheat flour was unbleached. In the 1900s, scientists invented a chemical process to bleach the flour.
Freshly milled wheat flour has a pale yellow tint, with pigmentation in amounts of 1.5-4 mg/kg expressed as carotenoid.1 These natural yellowish pigments affect bread crumb color. During flour storage, reactions occur among flour components, especially unsaturated lipids, and oxygen in a process known as aging or maturing. This process gradually whitens the flour over time.
Whiter flour is preferred in pan white bread baking because it results in better crumb color. However, the natural oxidation process for aging maturing wheat flour is time-consuming, requiring several weeks to months, thereby making natural bleaching unsuitable for modern milling and baking practices.1
Using chemicals can hasten the flour-bleaching process. For bread and all-purpose flour, the most common bleaching agent is benzoyl peroxide.1 It is added as a dry powder and whitens flour over a two-day period.1 It only bleaches flour pigments and has no effect on the breadmaking or baking properties.1
Since 1940, in the United States, all “family” flour and baker’s bread flour have been required to be enriched with the vitamins thiamin, riboflavin, and niacin, and with the mineral iron.2 The purpose is to replace part of the vitamins and minerals lost as a result of milling. Since 1998, flour in the United States is also supplemented with folic acid.2
For bleached flour, residual levels of both benzoyl peroxide and its reaction product benzoic acid have prompted health concerns. Benzoyl peroxide is a known tumor promoter and progression agent in mouse skin, though it is not an initiator or complete carcinogen.1 No bleached flours can qualify as organic.
The FDA regulated in article 21CFR137.105 of the Code of Federal Regulations that when any optional bleaching ingredient is used, the label shall bear the word “Bleached.”3 Benzoyl peroxide is GRAS as a bleaching agent in flour regulated by the FDA in article 21CFR184.1157.4
One part by weight of benzoyl peroxide may be mixed with not more than six parts by weight of one or any mixture of two or more of the following: potassium alum, calcium sulfate, magnesium carbonate, sodium aluminum sulfate, dicalcium phosphate, tricalcium phosphate, starch, calcium carbonate.3
- Lamsal, B.P., Faubion, J.M. Effect of an enzyme preparation on wheat flour and dough color, mixing, and test baking. LWT – Food Science and Technology 42.9 (2009):1461-7.
- Delcour, J.A., Hoseney, R.C. Chapter 8: Dry Milling. Principles of Cereal Science and Technology. 3rd ed. St. Paul, Minnesota: AACC International, 2010. p. 133.
- CFR – Code of Federal Regulations Title 21CFR137.105.” Accessdata.fda.gov. 01 Apr. 2016. www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=137.105. Accessed 08 July 2017.
- CFR – Code of Federal Regulations Title 21CFR184.1157. Accessdata.fda.gov. 01 April 2016. www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=184.1157. Accessed 08 July 2017.