Washed
soybeans (110 g) were soaked in 500 mL tap water in
1litre beaker at room temperature (28 C) for 16 h. After
the stipulated soaking time, the beans were drained and
ground with 1100 mL tap water in a Waring blender for
2 min at high speed. The mash was strained through a muslin
cloth and pressed to obtain soymilk. Soymilk (1000 mL)
was heated to boiling, and, then, mixed with 1.8%
MgCl2 Æ 6H2O alone or together with 0.05%, 0.1%, and
0.2% shell powder at 80 C, followed by being held for
15 min to coagulate. The curd was gently transferred to a
perforated stainless steel container (9.5 · 5.0 · 7.0 cm
depth) lined with a single layer of cheesecloth and pressed
for 15 min using bricks weighing 3.5 kg. The tofu was
immersed in the running tap water for 30 min, drained
for 30 min to remove excess moisture, and subjected to
the analysis and sensory evaluation.