猕猴桃切片中短波红外干燥特性及动力学模型

Drying Characteristics and Kinetics of Kiwifruit Slice under Mediumand Shortwave Infrared Radiation

摘要:

本试验研究了猕猴桃切片在不同的干燥温度（50、60、70、80 ℃）、干燥功率（675、1350、2025 W）条件下的中短波红外干燥特性试验，结果表明：干燥温度对猕猴桃切片干燥速率的影响较大，干燥温度越高，干燥用时越短；干燥功率对猕猴桃切片干燥时间影响较小；降速阶段为猕猴桃中短波红外干燥的主要阶段。通过对猕猴桃干燥动力学数学模型拟合发现：Page模型对猕猴桃切片干燥过程的拟合性较好，模型的预测值与实验值吻合性好，可以用来描述和预测猕猴桃的中短波红外的干燥过程。通过费克第二定律求出干燥过程中的水分有效扩散系数（Deff），发现其值在3.3970×10-9~1.2960×10-8 m2/s范围内，且随着温度和功率的升高而增大；通过阿伦尼乌斯方程计算出猕猴桃切片中短波红外干燥活化能在30.237~40.551 kJ/mol范围内。该研究为中短波红外干燥技术应用于猕猴桃的干燥提供了技术依据。

Abstract:

The experiment was carried out at different drying temperatures (50, 60, 70, 80 ℃) and infrared powers (675, 1350, 2025 W). The results showed that drying temperature had a significant influence on the drying rate of kiwifruit. The drying time decreased with the increase of the drying temperature and infrared power. The processing time of kiwifruit was less affected by the power. According to statistical parameters. The Page model was found to be the best to simulate medium and shortwave infrared radiation drying of kiwifruit slices among the six mathematical models. There was a good agreement between the experimental and predicted values. Since the medium and shortwave infrared radiation drying of kiwifruit slices was mainly dominated by falling period, the Fick’s second law of diffusion was employed to calculate the value of moisture effective diffusivity (Deff), which ranged from 3.3970×10-9 to 1.2960×10-8 m2/s, and increased with increasing the drying temperature and infrared power. The activation energy determined from Arrhenius equation was varied from 30.237 to 41.551 kJ/mol. This research provided the technique basis for the application of medium and shortwave infrared radiation drying technology in drying kiwifruit.