Experimental studies on the optimum convection drying temperature of sea cucumber

The process and characteristics of convection drying of sea cucumber(Stichopus japonicus) at a temperature range of 30～90℃ were studied. In order to determine the optimal conditions for efficient drying and get dried product with good quality after rehydration, the drying curves, rehydration ratios, rheological properties(i.e. elastic modulus, viscosity, stress-relaxation time and rupture strength) and sensory evaluations of sea cucumber were analyzed. The results show that the total drying of sea cucumber occurs only in falling rate period, because of moisture diffusion playing dominative rule during drying. At 30℃ the drying rate is the lowest; while at 45～90℃, drying rates are much higher, less time are needed and little time-consuming differences are shown in this range. As well, the products dried at 45～90℃ are demonstrated fine rehydration characteristics. The rheological properties and sensory evaluations of the rehydrated sea cucumber indicate that sea cucumber dried at 45～75℃ are relatively better. Considering the requirement of products quality and energy conservation, 45℃ was chosen to be the best process temperature.