热风干燥过程中榆叶叶黄素的降解动力学

目的：研究热风干燥过程中榆叶叶黄素的降解动力学。方法：采用高效液相色谱法测定榆叶中叶黄素的含量，对叶黄素降解过程进行反应动力学方程拟合，求解降解动力学参数。结果：新鲜榆叶中叶黄素含量较高，为（397.5±27.5）μg/g鲜质量（（1.414±0.105）mg/g干质量）。当风速为0.5 m/s，干燥温度为50、60、70 ℃时，榆叶中叶黄素的热降解符合一级反应动力学模型，半衰期分别为4.5、3.2、2.8 h；温度升高，降解反应速率增大；降解反应速率常数与干燥温度的关系符合Arrhenius公式，反应活化能为21.23 kJ/mol。结论：热风干燥榆叶时，采用较低的干燥温度有利于提高叶黄素保留率。

Degradation Kinetics of Lutein in Elm Leaves during Hot Air Drying Process

Purpose: This study aimed to determine the degradation kinetics of lutein in elm leaves during hot air drying
process at different drying temperatures. Methods: The content of lutein in elm leaves was determined by high performance
liquid chromatography (HPLC). The process of lutein degradation was fitted with a reaction kinetic equation and the
degradation kinetic parameters were resolved. Results: The content of lutein in elm leaves was (397.5 ± 27.5) μg/g fresh
weight (FW) or (1.414 ± 0.105) mg/g dry weight (DW). Analysis of kinetic data suggested a first-order reaction for the
degradation of lutein in elm leaves with the half-lives of 4.5, 3.2 and 2.8 h at 50, 60 and 70 ℃ , respectively. Increasing
temperatures from 50 to 70 ℃ enhanced the degradation of lutein during drying process. The temperature-dependent
degradation was adequately modeled on the Arrhenius equation. The activation energy value for the degradation of lutein in
elm leaves was 21.23 kJ/mol. Conclusion：Hot-air dried elm leaves at lower temperature can retain higher levels of lutein.