Influence of drying conditions on the effective moisture diffusivity, energy of activation and energy consumption during the thin-layer drying of berberis fruit (Berberidaceae)

Berberis is known as a medicinal and ornamental plant in the world. Berberis fruit is used in medicine to cure liver, neck and stomach cancer, blood purification and mouth scent. Dried berberis fruit using new technology was preserved for relatively long time. Thin-layer drying simulation was used to obtain experiment data, using laboratory scale hot-air dryer of the static tray. Fick’s second law was used as a major equation to calculate the moisture diffusivity with some simplification. The calculated value of moisture diffusivity varied from a minimum of 3.320 × 10−10 to a maximum of 9 × 10−9 m2/s and the value of energy activation from a minimum of 110.837 to a maximum of 130.61 kJ/mol of from 50 °C to 70 °C with drying air velocities of 0.5–2 m/s. The high value of the energy of activation for berberis fruit probably related to the tissue of berberis fruit and high moisture content (about 74.28%w.b), and intensive changes in Deff values for a different air temperature at constant air velocity. The input energy values and specific energy requirement for thin-drying of berberis fruit were found to be in the range of 0.643348–35.20032 (kWh) and 20.9355–1110.0700 (kWh/kg) from 50 °C to 70 °C with drying air velocities of 0.5–2 m/s, respectively.