1. Mechanism of soybean protein powder in flour
Soybean protein is rich in lipoxygenase, which is allowed to be used in most European countries. It is used as an auxiliary bleaching agent of benzoyl peroxide in baking and flour factories in North America. The enzyme has double functions in dough, one is to oxidize the pigment in flour to make it fade and make the inner tissue of bread white; the other is to oxidize the unsaturated fatty acid to form peroxide, which oxidizes the sulfhydryl group (- SH) in protein molecule to form disulfide bond (- S-S -), thus improving the gluten strength of dough.
Soybean protein has good water absorption, oil absorption, emulsification and other functional characteristics. After adding flour products, it can make the dough structure more delicate and elastic, better maintain the water content of flour products, improve water absorption, and delay the aging of products. The quality of bread can also be improved in the following aspects: ① the volume of bread increases; ② the skin color is good; ③ the skin is thin and soft; ④ the flavor is better.

2. Application and characteristics of soybean protein in flour processing
Compared with the common lipase, the whiteness and color of soybean protein powder increased more significantly. But too much will lose luster, similar to the effect of excessive oxidation bleaching agent. This side effect can be reduced by combining with common lipase. What is increased is the whiteness of flour products, which cannot be improved. In the production of noodles, browning can be delayed. Soybean protein powder belongs to the food category. It is not necessary to add less than 3% in flour according to FDA regulations. Generally, it is necessary to increase the amount of water after adding soybean protein powder.
3. Guidelines for soy protein addition
Soybean protein powder is relatively thick, so it can not be evenly added to flour by ordinary feeding. Therefore, the continuous and effective addition of soybean protein in flour can be realized by using Keyang automatic soybean protein feeder sdt-40 / 50. The soybean protein feeder is installed with horizontal mixing in the lower part of the hopper and vertical mixing in the hopper to prevent the bridging of the powder, so as to ensure the continuous and even output of the material. Thus, the problems of funnel flow, arching, overhead and uneven blanking are easily solved. It has been used in many flour mills.