title: Mathematical modeling on vacuum drying of Zizyphus jujuba Miller slices.
abstract: The thin-layer vacuum drying behavior of Zizyphus jujuba Miller slices was experimentally investigated at the temperature of 50, 60, and 70 °C and the mathematical models were used to fit the thin-layer vacuum drying of Z. jujuba slices. The increase in drying air temperature resulted in a decrease in drying time. The drying rate was found to increase with temperature, thereby reducing the total drying time. It was found that Z. jujuba slices with thickness of 4 mm would be dried up to 0.08 kg water/kg dry matter in the range of 180-600 min in the vacuum dryer at the studied temperature range from 70 to 50 °C. The Midilli et al. model was selected as the most appropriate model to describe the thin-layer drying of Z. jujuba slices. The diffusivity coefficient increased linearly over the temperature range from 1.47 × 10(-10) to 3.27 × 10(-10) m(2)/s, as obtained using Fick's second law. The temperature dependence of the effective diffusivity coefficient followed an Arrhenius-type relationship. The activation energy for the moisture diffusion was determined to be 36.76 kJ/mol.
authors.affiliation: Department of Food Science & Engineering, Daegu University, Gyeongsan, Gyeongbuk 712-714 Korea.
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Food Science & Engineering, Daegu University, Gyeongsan, Gyeongbuk 712-714 Korea.
authors.forename: Li
authors.initials: L
authors.lastname: Zuo
keywords: Activation energy; Drying kinetics; Effective diffusivity; Modeling; Vacuum drying; Zizyphus jujuba Miller slices