The mass balances of calcium salts during the manufacturing processes of Tofu were established by conductometric method and chemical analysis method. During the manufacturing processes of soy milk and Tofu, 66% of solid and 63% of calcium was transferred from soy-bean to the soy milk. and 47.8% of total solid from soybean was transferred to the Tofu, respectively.
When the CaCl₂ was used as coagulant, calcium contents in Tofu (Y_(Tofu), ㎎·Ca/g·Tofu. wet basis) and drained solution (Y_(drained soln), ㎎·Ca/㎖·drained soln.) were linearly increased with the amounts of CaCl₂(C, g·CaCl₂/㎖·soy milk) added in soy milk, and correlative equation, between them were obtained as
Y_(Tofu)=0.3369 C+1.2689
for Tofu (moisture content: 81.5±0.5%) with r=0.9898, and
Y_(drained soln)=0.2899C+0.0399
for drained solution with r=0.9991.
It was proved that conductometric method was reasonably applicable to the measurement of calcium contents of the products from every processes of Tofu manufacture except soy-bean. However the conductometric method was not recommendable in the case of CaSO₄ as coagulant due to its low solubility and uneven distribution in soy milk and Tofu tissue.
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