Drying Characteristics of Sea Cucumber (Stichopus japonicas Selenka) Using Far Infrared Radiation Drying and Hot Air Drying

摘要

Sea cucumber (Stichopus japonicus Selenka, SC) was dried using far infrared radiation drying (FIRD) and air drying (AD). The effect of the drying temperature of FIRD and AD on the drying rate of SC was investigated. Temperatures varied at 60, 70 and 80C, with a constant air velocity (13.2 m/s). Thin-layer drying models were applied to describe the drying process of SC with FIRD and AD. The Midilli and Kucuk equation showed the best fit (R 2  > 0.99). The effective moisture diffusivity (Deff) was estimated by the diffusion model based on the Fick's second law. The Deff values of FIRD and AD treated samples varied in the range of 3.39 × 10 −10 to 5.16 × 10 −10  m 2 /s and 2.81 × 10 −10 to 3.81 × 10 −10  m 2 /s, respectively. The activation energy (Ea) based on the drying temperature showed that the thermal sensitivity of FIRD was higher than that of AD. The scanning electron microscope images showed more damages on the surface of AD treated sample than that of FIRD. Practical Applications Dried sea cucumbers are highly value-added products. Currently, solar radiation is mainly used to produce the dried sea cucumber, but solar radiation drying requires more than 5 days under suitable environment. Such a long drying period causes sanitation problems as well as more cost to produce the dried sea cucumber. Our study showed that the far infrared radiation drying (FIRD) dramatically shortens the drying time. The quality of dried sea cucumber using FIRD was better than that of the air drying, because the surface hardening of the sea cucumber was minimized by the radiation heating mechanism. FIRD might be a good technology to replace the solar drying as well as the air drying to produce the dried sea cucumber.