Soybeans are soaked, ground and filtered to make paper pulp. It not only has many advantages of soybean nutrition, but also is superior to soybean in some aspects. Soybean milk contains a lot of soybean protein, which is a kind of high-quality plant protein and contains many essential amino acids, especially lysine, which can supplement the shortage of lysine in rice and flour. The digestibility of protein in soybean milk is about 20% higher than that of original soybean. Soymilk is also high in fat and rich in essential fatty acids. Helps promote growth and protect cardiovascular function. In addition, it also contains a considerable amount of calcium, iron and B vitamins. So the nutritional value of soybean milk is really high. In China, soybean milk is often used as a milk substitute for children over 3 months, or as a nutrient for the elderly who are allergic to milk protein. But some people eat uncooked soybean milk, which will cause food poisoning. What is the reason? Soybeans contain saponins, which can cause nausea, vomiting and indigestion; There are also some enzymes and other substances, such as trypsin, which will reduce the body's ability to digest protein; Cell agglutinin can cause coagulation; Urease glycosides will hinder iodine metabolism, inhibit the synthesis of thyroxine and cause compensatory goiter. But after cooking, these harmful substances will be destroyed, so soybean milk is harmless to human body. At present, iodine is added to the formula of soybean milk substitute to reduce the side effects of goiter. Finally, we must pay attention to the phenomenon of "fake cooking" when cooking soybean milk. Be sure to fully stir with a spoon until it really boils, and then give it to children to avoid soy milk poisoning.