Evaluation of microbiological, physicochemical and sensory qualities of chitosan tofu during storage

Tofu containing both low and high viscosity chitosan was prepared and changes in the microbiological, physicochemical and sensory properties of the tofu during storage were investigated. The colony forming units of mesophilic and psychrotrophic microorganisms in tofu containing high viscosity chitosan were markedly lower during storage than those in the control tofu as well as the tofu containing low viscosity chitosan. The pH of the tofu samples increased during storage. The L and a values of the tofu, especially the control tofu, increased during storage. In the sensory test, the roasted nutty and beany aromas of the tofu decreased during storage. Instrumental analysis of hardness and chewiness of the tofu decreased during storage. Overall preference for the tofu gradually decreased during storage, but overall preference for the tofu containing high viscosity chitosan scored higher than the other tofu samples.