Ma Yongcai, Liu Dan, Zhang Wei, Li Jun, Wang Hanyang
College of Engineering, Heilongjiang Bayi Agricultural University, Daqing 163319, China.
College of Food Science and Engineering, Henan University of Technology, Zhengzhou 450001, China.
ACS Omega. 2021 Jan 26;6(5):3951-3960. doi: 10.1021/acsomega.0c05824. eCollection 2021 Feb 9.
Hot-air coupled microwave was employed to dry lotus root slices. The effects of lotus root slice thickness (5, 8, 11, 14, and 17 mm), hot-air velocity (1.5, 2.0, 2.5, 3.0, and 3.5 m/s), hot-air temperature (50, 55, 60, 65, and 70 °C), and microwave power density (2, 4, 6, 8, and 10 W/g) on drying characteristics and kinetics were studied. Results indicated that the drying process involved both the accelerating and decelerating periods but no constant rate period. The drying rate reached the maximum of 1.52 kg/kg when microwave power density was 8 W/g and reached the minimum of 0.02 kg/kg at the last stage of drying. In addition, the drying kinetics of lotus root slices were also investigated using eleven previously reported models. Among the models, the Verma et al. model was the most suitable for description of the drying behaviors of lotus root slices based on , root-mean-square error, and chi-square. The moisture transfer from lotus root slices can be effectively described by Fick's diffusion model. Regardless of drying conditions, the effective diffusivity coefficients ranged from 8.23 × 10 to 7.08 × 10 m/s, and their variations were mostly in agreement with those of moisture ratios. The activation energy of moisture diffusion related to lotus root slices was determined to be 13.754 kJ/mol.
采用热风耦合微波干燥莲藕片。研究了莲藕片厚度（5、8、11、14和17毫米）、热风速度（1.5、2.0、2.5、3.0和3.5米/秒）、热风温度（50、55、60、65和70℃）以及微波功率密度（2、4、6、8和10瓦/克）对干燥特性和动力学的影响。结果表明，干燥过程包括加速期和减速期，但没有恒速期。当微波功率密度为8瓦/克时，干燥速率达到最大值1.52千克/千克，在干燥末期达到最小值0.02千克/千克。此外，还使用11种先前报道的模型研究了莲藕片的干燥动力学。在这些模型中，基于均方根误差和卡方检验，Verma等人的模型最适合描述莲藕片的干燥行为。莲藕片中的水分传递可以用菲克扩散模型有效描述。无论干燥条件如何，有效扩散系数范围为8.23×10至7.08×10米/秒，其变化大多与水分比的变化一致。确定与莲藕片相关的水分扩散活化能为13.754千焦/摩尔。
