食用槟榔热风干燥特性及动力学模型

Hot Air Drying Characteristics and Dynamics Model of Areca Catechu

摘要:

本文采用 Fick 第二扩散定律与槟榔干燥的数学模型研究了食用槟榔在不同干燥温度下的热风干燥特性、水分有效扩散系数、表观活化能等参数与干燥动力学方程之间的相互关系。结果表明：槟榔在 70 ℃与 75 ℃的干燥曲线有显著性差异（p<0.05），槟榔热风干燥是内部水分扩散控制的降速干燥过程；槟榔水分扩散系数变化范围：青果 Deff=6.45×10-9~1.17×10-8 m2/s，烟果Deff=7.47×10-9~1.21×10-8 m2/s；干燥表观活化能：青果 Ea=30.32 kJ/mol，烟果 Ea=23.38 kJ/mol。单项扩散模型与 Page 模型的常数项系 数受温度影响显著（p<0.05）；单项扩散干燥模型为描述食用槟榔的最佳数学模型(青果：R2avg=0.97，RMSEavg=0.023；烟果：R2avg=0.98，RMSEavg=0.025)；65 ~85 ℃ ℃热风干燥条件下的干燥模型可表述为：MR 青果=(2×10-4T2-0.037T+2.54)exp-(3×10-5T3-0.0064T2+0.51T-13.06)t；MR 烟果=(3×10-4T2-0.062T +3.67)exp-(-4×10-4T2 +0.061T-2.027)t，可为其干燥工艺的控制提供技术依据。

Abstract:

The relationships between the parameters of drying characteristics, effective moisture diffusion coefficient, apparent activation energy and the drying kinetics equations of Areca catechu in different temperatures were studied using the Fick’s second law and the mathematical model of betel nuts drying. The results showed that the drying curve of betel nuts at 70 ℃ and 75℃ had a significant difference; and the hot air drying was a process of falling-rate drying of internal moisture diffusion control. The variation range of water diffusion coefficient of Areca catechu (65℃~85℃) was as follows: friut areca catechu Deff =6.45×10-9~1.17×10-8 m2/s Smoke areca catechu Deff =7.47×10-9~1.21×10-8 m2/s. Apparent activation energy was: friut areca catechu Ea = 30.32 kJ/mol, smoke areca catechu Ea = 23.38kJ/mol. The constant coefficient of the single diffusion model and the Page model was significantly affected by temperature(p<0.05) and single diffusion drying model was the best mathematical model for describing edible areca (Friut areca catechu: R2avg =0.97, RMSEavg =0.023; Smoke areca catechu: R2avg=0.98, RMSEavg=0.025); The drying models of hot air drying at 65℃-85℃ were described as : MR Friut areca catechu =(2×10-4T2- 0.037T+2.54)exp-(3×10-5T3-0.0064T2+0.51T-13.06)t; MR Smoke areca catechu=(3×10-4T2-0.0616T+3.67)exp- (-4×10-4T2+0.061T-2.027)t.