Drying characteristics of sardine fish dried with microwave heating

Fresh fish contains up to 80% of water. It is a highly perishable material and having a short storage life. Therefore, the study of the drying kinetics of fish is necessary. In this study, the effect of microwave drying on drying rate, effective diffusivity, and energy consumption of sardine fish was examined at four different microwave powers (200, 300, 400 and 500 W). It was found that the moisture content was reduced from 2.76 to 0.01 (dry basis) and drying time of the samples was significantly reduced from 9.5 to 4.25 min as the power input increased. Five thin layer drying models were fitted to drying data. The Midilli model was selected as the best according to R2, χ2 and RMSE. The drying of fish samples took place in the falling rate period and was governed by moisture diffusion. The effective diffusivity varied from 7.158 × 10−8 to 3.408 × 10−7 m2/s over the microwave power range. No significant differences were observed between the specific energy consumption of microwave-dried sardine fish (α = 0.05). However, minimum specific energy consumption (3.78 MJ/kg water) was obtained at 500 W microwave levels.