Soy protein concentrate is made from defatted soybean meal as raw material. After removing non protein components such as soybean molasses, the protein content reaches over 65%, which is higher than domestic fish meal and some imported fish meal. The quality of soy protein concentrate mainly includes nutritional quality and processing quality, which are closely related to the protein content and the content and proportion of each component in soybeans. The protein components in soy protein concentrate are divided into four categories based on their solubility: albumin soluble in water, globulin soluble in dilute salt, gluten soluble in dilute alkali, and alcohol soluble protein soluble in ethanol. Albumin and globulin have physiological activity and can regulate various metabolic activities in body development, mainly affecting the nutritional quality of raw materials. Alcohol soluble protein and gluten protein are called storage proteins or gluten proteins, which mainly affect the processing quality of raw materials. Alcohol soluble proteins are rich in viscosity, extensibility, and expansibility; The content and composition of alcohol soluble protein and gluten determine the quality of protein processing and play an important role in the rheological properties of dough and other processing qualities.