Korean Journal of Agricultural Science ISSN:2466-2402(Print) 2466-2410(Online) 농업과학연구

Because lotus root has a short shelf life, the quality easily deteriorates. Thus, the harvested lotus roots are processed into a variety of products. Drying is one of the simplest food preservation methods, which can increase food stability. However, the convective drying method takes a long time and requires high energy consumption. Combination drying methods have emerged to overcome the limitations of the convective drying method. This study investigated the drying characteristics of lotus root and determined the optimal drying model of lotus root depending on the microwave and hot-air combination drying conditions. The lotus root slices (5 mm in thickness and 40 mm in diameter) were dried by different drying conditions that were combined with three microwave power levels (50, 100, and 150 W) and two hot air temperatures (50 and 60℃) at a velocity of 5 m·s-1. Eight drying models were tested to evaluate the fit to the experimental drying data, and the effective moisture diffusion (Deff) values of the lotus root slices dried by combination drying were estimated. The combination drying time of the lotus root was significantly reduced with the high air temperature and microwave power. The effective moisture diffusion (Deff) of lotus root was more affected by the air temperature than microwave power intensity. Logarithmic model was most suitable to describe the drying curve of lotus root in the microwave-hot air combination drying method.