Abstract
A controlled coagulation system applying torque measurement was developed in order to investigate the related factors. From the characteristic rise of torque curve, proper amounts of coagulant could be determined automatically. The coagulated soymilk reacted with steadily added calcium chloride by this system, molded to intermediate "tofu" and then frozen and dried to final product "kori tofu". The optimum coagulation conditions were precisely examined at the various reaction conditions of concentration of soymilk, reaction temperature, and concentration of coagulant. The relationships between the torque changes and the properties of tofu and kori-tofu were also investigated.
Through a series of coagulation and pressing experiments with this new system, following results were obtained. (1) Determination of the required amount of coagulant as well as the on-off control of stirring of soymilk are performed automatically. (2) The optimum initial concentration of soymilk was around 5% from the view point of water holding capacity of the dried kori-tofu. (3) The higher temperature, between 54 and 70°C, shortened the pressing time, hardened the tofu curd in one hand and decreased the water holding capacity of kori-tofu in the other. The optimum temperature was 60 to 65°C. (4) The optimum concentration of calcium chloride was around 10mM in the present experimental conditions.
These findings contributed to the semi-automated processing and the products of fine properties.
