When the dough made of wheat flour is kneaded and washed in water, the starch and bran particles are suspended and separated, the other parts are dissolved in water, and the remaining elastic and sticky gelatinous substances are called gluten. The main components of wheat gluten are gliadin and glutenin, accounting for about 80% of the total gluten, and also containing a small amount of starch, fat and sugar. Generally, wet gluten contains 2/3 moisture, and dry matter accounts for 1/3. Wheat flour can be processed into a wide variety of foods because of its unique gluten, which many crops do not have. People classify the quality of wheat according to gluten content in order to process different types of special foods.

Reasonable application of nitrogen fertilizer can effectively increase the content of dry gluten and wet gluten. The results showed that the dry gluten and wet gluten contents of common medium gluten wheat increased with the increase of nitrogen application rate, and the dry gluten content increased from 7.64% to 13.23%, which was a relative increase of 73.2%. The wet gluten content increased from 19.72% to 32.09%, so increasing nitrogen fertilizer has a very obvious effect on improving gluten content.