The water content of tofu depended on the methods of preparation (Table 2). GDL tofu contained thelargest amount of water, while gypsum tofu had the smallest amount of water. The addition of chitosan increased the water content slightly for tofu prepared using GDL and gypsum. But it decreased the water content of the tofu prepared with acetic acid by 1–3%. Consequently, for the samples that contained chitosan,the acetic acid tofu had the lowest water content. These results indicated that chitosan bound with more water in the presence of GDL and calcium ions. However, in an
environment containing acetic acid, it became much more hydrophobic and excluded more water from the gel. The water content of samples differed slightly for samples containing chitosan of different DD. These results suggest that one order of magnitude difference in
the Mw of chitosan (from 106 to 105) did not cause a
significant change in its water holding capability. Water
content of tofu samples seemed to have less influence on
their gel strengths than the DD of chitosan. However,
the lower water content acetic acid tofu had the highest
gel strength and longest shelf life. This suggested that
water content also had substantial influence on the gel
properties of tofu.