Abstract: The present work was done to optimize the process conditions for cold-air drying (CAD) of pickled Apostichopus japonicus by the combined use of one-factor-at-a-time method (OFAT) and response surface methodology (RSM). The response variable was the weighted average of sensory scores and dehydration rate. A comparison of CAD, vacuum freeze drying (VFD), hot-air drying (HAD) and vacuum microwave drying (VMD) was performed in terms of the quality of dried products. Results?showed that?the optimal cold-air drying conditions were determined as follows: vacuum desalination time, 4.2 h; drying temperature, 19 ℃; and wind speed, 1.70 m/s, resulting in a weighted average of 0.77. With respect to nutrient retention, VFD and CAD were?better than HAD and VMD. In terms of heat?shrinkage, the drying methods were in the decreasing order of HAD, VMD, CAD and VFD with only a marginal difference being observed between CAD and VFD, while they followed the decreasing order of CAD, VFD, HAD and VMD in terms of rehydration rate. In terms of textural characteristics, CAD and VFD were better than HAD and VMD. These?results?showed?that CAD was more practical in industrial production.

Key words: Apostichopus japonicus, cold-air drying, response surface methodology, textural characteristics, sensory characteristics