Dynamic characterization of moisture diffusion behavior in a fish paste sausage during poultice up process operated in the course of forced ventilation drying

摘要

Unsteady state behavior of moisture transfer during a poultice up process which has been applied to uniform distribution of moisture content in the course of forced ventilation drying of foods was characterized by using a fish paste sausage. For the quantitative analysis of moisture transfer, effective diffusivity (D_e) and activation energy of moisture diffusivity (E_0) were evaluated. The characteristic behavior of D_e obtained was classified into two regions depending on the value of moisture content (W_0) in the sausage:Region I (W_0> 100%-d.b.) in which D_e at 50 deg C was decreased from 2.7 X 10~(-6) to 1.6 X 10~(-6) m~2/h with decreasing W_0 and region II (W_0< 100%-d.b.) in which D_e gave 1.6 X 10~(-6) (+-0.2) m~2/h without depending on W_0. E_e's at regions I and II were evaluated as 16.5 (+- 1.0) and 9.6 (+-0.6) kJ/mol, respectively. Based on the results obtained, it was considered that the mechanism of moisture transfer and the physicochemical structure of water distributed in the sausage should differently be characterized between regions I and II.