Effect of carrageenan on yield and properties of tofu

The effects of the polysaccharide carrageenan and three types of coagulants namely, glucono-δ-lactone (GDL), calcium sulphate (CS) and calcium acetate (CA) on yield and physical properties of tofu (soybean curd), were investigated. Moisture content and yield of GDL-coagulated tofu were higher than that coagulated with CS and CA. Addition of carrageenan did not increase yield of GDL-tofu significantly but increased yield of CS-tofu and CA-tofu by 33 and 46.7%, respectively. Texture of CS-tofu was harder than CA- and GDL-tofu. Carrageenan brought about a significant decrease in hardness of CS- and CA-tofu which was more pronounced at the higher gum concentration. Hardness of GDL-tofu was not significantly altered. The tofu gels exhibited syneresis on storage at 4°C for 24 h in the order: CS-tofu<CA-tofu<GDL-tofu. Addition of carrageenan increased the syneresis, which was higher in CA-tofu than CS-tofu. On the other hand, GDL-tofu showed a decrease in syneresis in the presence of carrageenan. ©