During the milling process, due to the action of mechanical forces, the protein (-S-S-) bond in flour is broken into (-SH) bond, which reduces the strength and gas retention of gluten. The (-SH) and (-S-S -) bases in the flour determine the strength of the dough, and the more (-SH) bases are converted into (-S-S -) bases, the stronger the dough strength. 

This transformation mainly relies on oxidation, the main oxidants are potassium bromate, potassium iodate, Ascorbic Acid, Azodicarbonamide, etc., because it can improve the dough strength, also known as flour strong reinforcement agent.

Potassium bromate

Potassium bromate is a chronic reactive oxidant, is largely ineffective in the flour mixing process ‚ but is active during fermentation. It has great influence on all the indexes in the silty tensile curve. However, it has little effect on the extension , while the resistance to extension is greatly increased , and the volume of bread is greatly affected. With the increase of adding amount, the volume of bread increases, but after reaching a certain extent, the volume of bread no longer increases. The maximum allowable addition amount is 0.03 g/kg.

Vitamin C

Vitamin C is chemically amphoteric, that is, both oxidizing and reducing. During agitation, produces dehydrogenation, due to sufficient oxygen during fermentation, the absorption of oxygen atom becomes the main reaction, reduces -SH in gluten, -S-S - increases. Vitamin C is a medium acting agent, does not work in dry flour. The reaction takes place during stirring and fermentation. It has a great effect on various indexes in the silt tensile curve. Compared with other oxidizing agents, it has the greatest effect on the extension and elasticity of dough, the extension range is reduced, and the resistance to extension is greatly increased.

Vitamin C is a nutritional fortification, non-toxic side effects. It can also enhance the nutritional value of flour. Therefore, it is relatively safe to use. It can increase bread volume and improve bread structure.

Azodicarbonamide (ADA)

Azodicarbonamide is a highly effective oxidizing agent used as a fast starter for baked goods. At low dose, it can satisfy the oxidation of wheat flour and maintain the oxidation activity for a long time. In the water environment (under wet conditions), Azodicarbonamide reacts with the sulfhydryl bond (-SH) of the amino acid in the wheat flour protein, making it remove the hydrogen atom and transform into disulfide bond (-S-S -), and then the protein chain is connected to form a network structure, so as to strengthen the wheat flour gluten.

Azodicarbonamide has a similar effect to potassium bromate, but unlike potassium bromate, which is a slow oxidizing agent, the wheat flour product with azoformamide is activated immediately after contact with water, so that the dough reaches maturity quickly during the dough mixing process.

When the addition of Azodicarbonamide in wheat flour is 35 mg/kg, the dough tensile resistance is enhanced and the elongation is weakened to reach an optimal ratio, so the bread produced is the most elastic, the largest volume, and the best quality. The maximum dosage is 45 mg/kg, and the recommended dosage is 10-20 mg/kg.

Calcium peroxide

The effect on dough is also rapid, similar to vitamin C. After addition, the silty curve becomes bimodal ‚ and the elongation resistance in the tensile curve increases greatly, and the elongation decreases greatly. Less used than other oxidants.

Glucose oxidase

In the presence of oxygen, glucose can be converted into glucose-saccharic acid, and hydrogen peroxide is produced. Hydrogen peroxide is a strong oxidizing agent, which can oxidize the lucyl group (-SH) in the gluten molecule to the disulfide bond (-S-S-), thereby enhancing the strength of gluten.

Glucose oxidase can significantly improve flour properties, prolong stability time, reduce softening degree, improve evaluation value, improve flour stretching characteristics, increase tensile resistance, improve flour gelatinization characteristics, increase maximum viscosity, reduce damage value, and form a more stir resistant, dry and non-stick dough. 

Because of its natural, non-toxic and no side effects, Glucose oxidase has been widely used in the food industry in recent years to replace potassium bromide or Azodicarbonamide.

The optimal addition amount is 0.04%. Glucose oxidase can effectively enhance the bite strength of noodles and improve the surface state of noodles. The steamed bread produced has loose internal organization, large mesh, spongy shape, delicate and gentle taste, and better elasticity and toughness.

In addition, Vital Wheat Gluten,  and soybean flour also has the effect of enhancing gluten.

Active gluten is a kind of natural protein, mainly used in flour with weak strength, which can improve the gluten content and quality of flour, and can significantly improve the water absorption of dough, so as to achieve the purpose of keeping fresh without aging and extending the storage life. Vital Wheat Gluten, for example, can enhance the dough's air retention, water retention and increase the volume of bread, improving the organization of bread.