Generally, syneresis is pertinent to cross-linking among protein molecules .Here, the results demonstrated that all of the three polysaccharides affected syneresis in tofu in a greater extent than tofu coagulated by MgCl2. With the addition of 0.2 g carrageenan, syneresis was reduced by 1.25%, which could be caused by the extensive network structure developed by carrageenan. As a consequence more water was trapped in interstitial parts of the tofu gel.Interestingly, with 0.6 g carrageen,tofu syneresis increased .It was postulated that as the concentration of carrageenan increased, quicker gel formation was initiated, leading to a coarse net structure and less water being retained .For polysaccharides which have no gelling effects, guar gum and gum Arabic only affected the coagulation rate of tofu; however, both of them increased the syneresis. The increased syneresis of protein gel was suggested to be caused by the increased crosslinking among protein molecules through various interactions, which allowed the exuded water to be trapped within the gel.Increase of guar gum to 0.6 g also increased the syneresis to 5.43%. While this effect may be due to the increased protein aggregation by guar gum ,the effect of gum Arabic on tofu may be related to the fact that gum Arabic molecules aggregate themselves and become compact by means of a draining effect. In this current study, all of the tofu products were light yellow ,suggesting the quality of the tofu was good, as good quality tofu is supposed to be light yellow or white in colour.
The addition of carrageenan increased the value of b (yellowish) significantly, suggesting it may improve the quality of tofu.