Modeling of ultrasonic-convective drying of pistachios

The combination of high power ultrasound and convective air for drying of pistachios (Akbari variety) was performed in a laboratory scale ultrasonic dryer, which was constructed for this purpose. The drying rate curves show that first rapidly decreased and then very little reduction in moisture ratio observed with increase of drying time. A non-linear regression Logarithmic model represents good agreement with experimental data with coefficient of determination and mean square of deviation as 0.9885 and for 150 Watt and 0.9890 and for 300 Watt acoustic power respectively. In fact, at two ultrasonic powers, the mathematical drying models were similar