tudy on moisture desorption isotherm and thermophysical property for Red sea bream Chrysophrys major Temminck et Schlegel

Abstract:

This paper aimed at the kinetic character of moisture desorption isotherms, the relationships between unfrozen water and freezing point and thermodynamic of red sea bream Chrysophrys major Temminck et Schlegel. Differential scanning calorimeter (DSC) and water vapor pressure capacitance manometer were applied to study the water activity (aw), enthalpy of water fusion (ΔHf) and freezing point. Experimental data were modeled by the Guggenheim Anderson de Boer (GAB) and the Brunauer, Emmett and Teller (BET). Moisture desorption isotherms of red sea bream exhibited the sigmoid (Type II) shape. The GAB model gave the better fit (R2=0991 5) to the experimental sorption data for a wide range of water activity (013~098) while the BET model gave the worse fit (R2=0982 5) for a water activity range of less than 090. Monolayer moisture content was computated through the two models, which was 0082 0 g/g dried base (GAB model) and 0078 1 g/g dried base (BET model). Liner equation about ΔHf and frozen water content were applied（R2 = 0999 6） for red sea bream. And from the equation, the unfrozen water content were calculated to be 0291 2 g/g dried base, at the time of ΔHf=0.