Flour bleaching agent is the agent added to fresh milled grains to whiten the flour by removing the yellow colour pigment called xanthophyll. It whitens the flour, which is used in the baking industry.
Overview
Usual flour
bleaching agents are:
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Organic peroxide
In organic chemistry, organic peroxides are organic compounds containing the peroxide functional group (). If the R′ is hydrogen, the compounds are called hydroperoxides, which are discussed in that article. The O−O bond of peroxides easily ...
s (
benzoyl peroxide
Benzoyl peroxide is a chemical compound (specifically, an organic peroxide) with structural formula , often abbreviated as (BzO)2. In terms of its structure, the molecule can be described as two benzoyl (, Bz) groups connected by a peroxide () ...
)
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Calcium peroxide
Calcium peroxide or calcium dioxide is the inorganic compound with the formula CaO2. It is the peroxide (O22−) salt of Ca2+. Commercial samples can be yellowish, but the pure compound is white. It is almost insoluble in water.
Structure a ...
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Chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is ...
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Chlorine dioxide
Chlorine dioxide is a chemical compound with the formula ClO2 that exists as yellowish-green gas above 11 °C, a reddish-brown liquid between 11 °C and −59 °C, and as bright orange crystals below −59 °C. It is usually ...
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Azodicarbonamide
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Nitrogen dioxide
Nitrogen dioxide is a chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the productio ...
*Atmospheric
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as we ...
, used during natural aging of flour
Use of chlorine,
bromate
The bromate anion, BrO, is a bromine-based oxoanion. A bromate is a chemical compound that contains this ion. Examples of bromates include sodium bromate, (), and potassium bromate, ().
Bromates are formed many different ways in municipal drin ...
s, and
peroxide
In chemistry, peroxides are a group of compounds with the structure , where R = any element. The group in a peroxide is called the peroxide group or peroxo group. The nomenclature is somewhat variable.
The most common peroxide is hydrogen ...
s is not allowed in the
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been ...
.
Bleached
flour
Flour is a powder made by grinding raw grains, roots, beans, nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredient of bread, which is a staple food for many c ...
improves the structure-forming capacity, allowing the use of dough formulas with lower proportions of flour and higher proportions of
sugar . In
biscuit
A biscuit is a flour-based baked and shaped food product. In most countries biscuits are typically hard, flat, and unleavened. They are usually sweet and may be made with sugar, chocolate, icing, jam, ginger, or cinnamon. They can also be ...
making, use of chlorinated flour reduces the spread of the dough, and provides a "tighter" surface. The changes of functional properties of the flour
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...
s are likely to be caused by their
oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...
.
In countries where bleached flour is prohibited,
microwaving plain flour produces similar chemical changes to the bleaching process. This improves the final texture of baked goods made to recipes intended for bleached flours.
See also
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Chorleywood bread process – another bread making process that increases volume
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Flour treatment agent
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Graham flour
Graham flour is a type of coarse-ground flour of whole wheat named after Sylvester Graham. It is similar to conventional whole-wheat flour in that both are made from the whole grain, but graham flour is ground more coarsely. It is not sifted ( ...
– an early unbleached whole-grain flour
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Maida flour
is a white flour from the Indian subcontinent, made from wheat. Finely milled without any bran, refined, and bleached, it closely resembles cake flour. is used extensively for making fast foods, baked goods such as pastries, bread, several vari ...
– a commonly bleached flour in India
References
Food additives
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