Texture and Microstructure of Soybean Curd (Tofu) as Affected by Different Coagulants

The coagulating properties of five coagulants and the nature of the curd obtained from soymilk was investigated . Viscosity changes during coagulation were studied using a Namctrc Vibrating Sphere Viscometer and texture measurements were made by compression and computer assisted analysis. pH and amount of solids in the whey were determined. The microstructure of the tofu was examined by sca nning electron microscopy. It was observed that CaCI2.2H20 and MgCI2.6H20 coagulaled the milk in stantl y while CaS04 .1/2H20. glucono delta l a~tonc (GOL) and MgS04 .7H20 acted comparatively slowly. The t exture of the curd was greatly influenced by type and concerHra tion of coagulant. Curd obtained with CaCI2.2H20 and MgCI2.6H20 was coarse, granular and hard , whereas CaS04. I/2H 20 and GDL (fresh solution) gave a very smooth . soft and uniform curd . Among the five coagulants studied, 0.75% CaSO_. and 0.4% GDL (fresh solution) appeared to be most suitable for making tofu of high bulk weight and smooth texture