Change in dielectric properties of sweet potato during microwave drying.

Abstract

Sweet potato slices and strips (thickness of 6 and 9mm, respectively) as single layer were dried at different microwave power levels (90W to 900W) in order to determine the effect of microwave power and sample shape on drying characteristics. Dielectric properties of sweet potato slices were measured during microwave drying. Drying time for both samples was decreased with increase in microwave power, and drying time of strips was longer than slices inthe microwave power range between 90 and 720W. Page model was suitable for describing experimental drying data regardless of microwave power and shape of sweet potato samples. Dielectric properties of sweet potato slices were decreased with a decrease in moisture content. The change in dielectric properties of sweet potato slices could be predicted by Henderson and Pabis model and could be applied to estimate the change in moisture content of sweet potato during microwave drying.