What is the principle of making traditional tofu?

The main ingredient of soybean milk is protein. Due to the carboxyl and amino groups on the surface of protein, colloidal substances with the same charge are formed on the surface of protein particles, so that the particles repel each other and cannot sink together.

After the brine is lit, because there are many electrolytes in the brine, many positive and negative ions are formed in the water, which destroys the repulsion and makes protein combine with precipitation to form tofu.