1. The impact of wheat quality
Overall, the main wheat producing areas in China are concentrated in Shandong, Anhui, Henan, Hebei, and Jiangsu provinces. Due to regional natural conditions and agricultural planting structure, the whiteness of flour increases from north to south. This is mainly determined by the wheat variety. The hard gluten wheat in northern cities gradually evolved into soft powdery wheat in the south. So, the flour from the south is naturally the old white from the north. Even with the same dosage of whitening agent added, it still appears as white from the south. Similarly, flour mills in the north purchase different raw materials. Due to the higher price of hard wheat compared to soft wheat in the market, many flour mills purchase soft wheat at low prices in order to reduce costs. They even transport soft wheat from the south to mix with local wheat, reducing costs and improving flour whiteness. It also affects the taste and odor of the flour.
2. The impact of processing technology
During the processing of flour, some bran particles will enter the flour, and the quality of the processing technology directly affects the whiteness of the flour. The early methods of making sacron flour had to be forced due to the short flour path and the need to consider the flour yield, resulting in a higher amount of gluten in the flour and affecting its color.
In addition, if the flour is too fine, it will cause excessive grinding strength. On the surface, the whiteness of the flour will be high, but the whiteness of the food produced will actually decrease. The reason is excessive grinding, causing the bran to be so fine that it cannot be distinguished by the naked eye, but it is actually present in flour. Once used for processing, it immediately reveals its original form.
3. The impact of powder yield.
The flour we purchase at the terminal, such as Te Er Fen, is actually a mixed flour, which is a mixture of all the front, middle, and back flour. Macroscopically speaking, the main component of the front flour in flour processing is the wheat core, while the main component of the middle flour is the majority of the wheat endosperm. Hind flour is a layer of flour that is located near the surface of wheat. In theory, the flour in the front is less likely to mix with bran due to the fewer grinding times, resulting in a whiter flour, while the flour in the back is the opposite. So, the whiteness of wheat flour will be higher than that of fine flour, and the whiteness of special fine flour will be higher than that of one pink.
4. The impact of flour additives.
Whitening agent is a commonly used food additive in the flour industry, mainly used to bleach flour. Its main component is a strong oxidant called benzoyl peroxide (with a content of 28%). The mechanism of action is to oxidize and decompose lutein in flour in a short period of time, thereby achieving the effect of bleaching. The flour without added whitening agent has a yellow white color, which is brighter. After adding whitening agent, the color turns pale white. The national standard for addition is 2/10000, but some manufacturers increase the amount of addition without authorization in order to increase whiteness. Taking Te Er powder as an example, the whiteness of the flour after being processed is around 78 degrees. The whiteness after oxidation with the addition of 2/10000 whitening agent can reach 81 degrees, and the whiteness after oxidation with the addition of 4/10000 whitening agent can reach 82-83 degrees. The use of whitening agents satisfies people’s need for food aesthetics. At the same time, it also destroys some nutrients in the flour. Lutein contains many nutrients, such as carotenoids, which are raw materials for synthesizing various vitamins required by the human body. The destruction of lutein can directly lead to the deficiency of many trace elements required by the human body, such as vitamins A, B1, B2, B6, C, folic acid, niacin, etc. Especially when using whitening agents beyond the standard, the content of benzoic acid (the main component of preservatives) in flour is high, which is very harmful to human health.