What does Bleached flour mean?
Bleached flour is obtained when the endosperm part of the wheat grain is milled into flour which is later treated with a chemical bleaching agent. Such bleaching agents that can be used include nitrosyl chloride gas, and/or nitrogen oxides, chlorine dioxide, hydrogen peroxide, calcium dioxide, azodicarbonamide, and benzoyl peroxide.
Benzoyl peroxide is the most popular bleaching agent used to improve the color of the wheat from a pale or off-white appearance (due to the presence of carotenoids) to a much more desirable white color and at the same time improve the texture of the flour. Its popularity may be because it does not influence the taste of the flour even when used for baking. Furthermore, bleaching of flour has been noted to speed up the maturation process of wheat flour and also accelerate the breakdown of the protein- a time-saving production hence, the preference for bleached flour production.
However, health risks like cancers have been associated with the use of benzoyl peroxide and in this effect, its usable concentration is highly regulated by the government of each country as well as international organizations.
The bleaching process involves the brake down of the conjugated double bond of carotenoids to a less colorless system with a whiter appearance and a desirable softer texture suitable for baking.
It is of great importance to note that during the bleaching process of wheat flour, a toxic substance known as alloxan is produced especially when chlorine dioxide is used as a bleaching agent. This toxic substance is reported to induce kidney damage at high blood as well as type 1 and type 2 diabetes. However, its higher concentration is mainly identified in raw bleached flour but could not be traced to flour-based baked products. This is assumed to be because the baking heat destroys alloxan- a piece of good news for baked food consumers but bad news for those that indulge in eating raw bleached flour-based foods like raw cookie dough.
However, another procedure that does not involve the use of chemicals has been identified to equally have a bleaching effect on wheat flour. As a means to reduce the microbial load of the Salmonella spp. often associated with low-moisture foods like wheat flour, ultraviolet pulses(395nm) emitted from the light emitting diode(LED) were used in place of other thermal heat treatments of the wheat flour and the results showed an antimicrobial potential with an additional non-chemical bleaching effect.
Nutritionally, bleached flour is negatively affected due to the actions of the bleaching agent but its nutrient value can be improved through enrichment.
What is Unbleached flour ?
Just like bleached flour, unbleached flour is obtained when the endosperm which is gotten after the wheat bran and germ have been mechanically separated from the wheat grain is milled into flour. Unbleached flour has a pale yellow color due to the presence of carotenoids present in the wheat endosperm.
After the milling process, the wheat flour is kept in storage for its maturation process to occur naturally on exposure to oxygen in the atmosphere (and oxidation of the carotenoids occur) which causes an off-white color to the flour (this contact with oxygen also contributes to its discoloration).
Although there may be health risks associated with the consumption of unbleached flour,
Similarities between bleached and unbleached flour
Health risks related to bleached and unbleached flour
Consumption of both bleached and unbleached flour has been associated with the development of Celiac disease which is a genetic auto-immune disease. What happens is the body’s immune system responds to a perceived threat triggered by the presence of the tTG enzyme which is attached to undigested gluten fragments and attacks them. This attack results in damage to the bowel surface and the intestinal lining thus interfering in nutrient absorption into the bloodstream and this is a big health risk for the development of diseases.
A dietary lifestyle that involves the consumption of bleached and unbleached flour products can also result in non-Celiac gluten sensitivity. The symptoms occur outside of the intestine and can manifest hours to days after their bodies have been exposed to gluten in the form of headaches or eczema.
The absence of fiber in bleached and unbleached wheat flour products results in their slow metabolism when consumed and can lead to weight gain or even stress. Other diseases which can be triggered due to the consumption of bleached and unbleached flour include diabetes mellitus (due to high glycemic index).
Furthermore, there has been a link between gluten sensitivity and psychiatric disorders like bipolar.
Production process involved in bleached and unbleached flour
Both flour types are obtained when the endosperm which is gotten after the wheat bran and germ have been mechanically separated from the wheat grain is milled into flour. After the milling process, they are subjected to a maturation process which also affects their color profile.
Uses of bleached and unbleached flour:
Bleached and unbleached flour can be used for different varieties of cooking recipes like baking and making gravies, depending on personal preferences. They can also be used interchangeably
Enrichment in bleached and unbleached flour:
Due to the nutrient loss as a result of milling and bleaching processes, both bleached and unbleached flour can be fortified as a public health measure to replace lost nutrients and also to serve as a source of some essential nutrients that are not consumed in sufficient quantity.
Treatment of bleached and unbleached flour:
After the milling process, both flour types technically undergo bleaching treatment through chemical agents or natural oxidation. These processes result in the weakening of the proteins thereby improving the texture and affecting their color along the line as they age (although the processing time differs for each flour type).
Frequently Asked Questions
Is bleached and unbleached flour the same?
No, bleached and unbleached flour are not the same. As the name implies for bleached flour, a bleaching agent like benzoyl peroxide is been used to remove the pale yellow color often associated with milled wheat flour (unbleached) due to the presence of carotenoids to achieve the whiteness often associated with it.
Is unbleached flour the same as regular flour?
Yes, unbleached flour is the same as regular flour.
What is the nutritional difference between bleached and unbleached flour?
Nutritionally, bleached and unbleached flour is the same.
What does unbleached flour look like?
Bleached wheat flour has a pale yellow color due to the presence of carotenoids.
What is unbleached flour from?
Unbleached flour can be sourced from any type of whole wheat grain
What is the purpose of unbleached flour?
The purpose is for consumers to have access to wheat flour void of any chemical agent and impending health risks associated with the consumption of the bleached counterpart.
Is unbleached flour safe to eat?
Yes, unbleached flour is safe to eat because it does not contain any harmful chemical agents.
Is unbleached all-purpose flour better?
Yes, unbleached all-purpose flour is better because it does not contain any chemicals. Furthermore, it can be a combination of hard and soft wheat flour which is a good attribute when it comes to baking.