The amount of coagulant added to soymilk is a critical factor for tofu manufacturing, especially affecting product yield and texture.The addition of a higher amount, instead of an optimal amount, leads to increased whey and lower tofu production.Moreover, the resulting tofu is harder, and, under extreme situations (in which higher concentrations than the optimum concentration are added), tofu resembles a precipitate rather than a gel. Prior knowledge of
the optimum coagulant concentration (OCC) is essential, especially for quick-acting coagulants. Studies have been conducted on CaCl2 and MgCl2; however, there are no reports on the use of MgSO4 in firm tofu preparation, which is very common in Brazil. The OCC can be determined by the titrimetric method developed by.