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

Abstract

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 (R2 > 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 m2/s and 2.81 × 10−10 to 3.81 × 10−10 m2/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.

Effects of processing method on chemical compositions and nutritional quality of ready‐to‐eat sea cucumber (Apostichopus japonicus)

“…These products have to be rehydrated in cold water for more than 2 days and then subjected to a complex cooking procedure before consuming (Ferdouse, 2004;Ji, Kim, Dong, Pan, & Yoon, 2014). Most of sea cucumbers are processed into dried or salted products to facilitate storage and transport.…”

The effect of different drying methods on chemical composition, fatty acid, and amino acid profiles of sea cucumber (Holothuria tubulosa Gmelin, 1791)

“…This process is carried out at 18°C–25°C for 72–96 hr (Li et al, ). However, this traditional method leads to problems such as long processing time, loss of many active compounds, inadequate removal of water, and contamination during the process (Duan, Zhang, Mujumdar, & Wang, ; Moon, Kim, Chung, Pan, & Yoon, ). Hot air drying, microwave drying, and freeze drying are alternatives to sun drying method.…”

“…For this reason, it is important to choose a drying method that will protect nutritive and bioactive substances in sea cucumbers, as well improve the quality of products (Li et al, ). In addition to these methods, researchers have used drying methods such as microwave freeze drying (Duan et al, ), dielectric drying (Duan, Zhang, Mujumdar, & Wang, ), combined electrohydrodynamic and vacuum freeze drying (Bai, Yang, & Huang, ), and far infrared radiation (Moon et al, ) to dry sea cucumbers.…”

“…Hot air dryers provide a faster, homogenous, and hygienic drying than sun drying method (Doymaz & Pala, 2002;Li et al, 2018). But hot air drying causes major product deteriorations (Moon et al, 2014;Ratti, 2001). Microwave energy is widely used in the drying of food products.…”

Drying characteristics and thermal degradation kinetics of hardness, anthocyanin content and colour in purple‐ and red‐fleshed potato (Solanum tuberosum L.) during hot air drying

“…The E a values for PFP and RFP were 22.85 and 23.94 kJ mol −1 , respectively. The physical meaning of the E a value from the sample could be interpreted as the amount of energy required to transfer the moisture through the samples being dried (Moon et al ., ). In this study, the activation energy for the PFP was slightly lower than that of the RFP, which indicated that hot air dying of the PFP required slightly less energy than the RFP.…”