Microwave Penetration Depth in Bulk Pistachios

The microwave penetration depth in bulk pistachios were determined as a function of the temperature between 50 to 90°C, moisture content from 3.3% to 51.5% at frequency 2.450 GHz. Maximum penetration depth was calculated at 60.35 mm when bulk pistachios have 51.5% moisture content at 50°C and minimum 6.34 mm for 11.5% moisture content at 90°C. The penetration depth slightly decreased to a temperature of 70°C. A multiple regression equation for predicting penetration depth was formulated. These results are expected to provide useful data for designing microwave heating processes of pistachios.

Bulk pistachios, Microwave heating, Dielectric properties, Penetration depth, Moisture content