金银花气调热泵干燥过程中绿原酸降解动力学研究

Degradation Kinetics of Chlorogenic Acid in Honeysuckle during Modified Atmosphere Heat Pump Drying

为探讨金银花气调热泵干燥过程中绿原酸含量及外观色泽的变化规律,本实验以金银花为研究对象,以N2为干燥介质置换空气降低设备中氧体积分数,研究温度、装载量和氧体积分数对绿原酸含量和L值的影响,建立绿原酸降解动力学模型。结果表明:达到干燥终点时,金银花的绿原酸含量和L值随干燥温度、装载量和氧体积分数的升高而降低;通过向一级反应动力学方程中的干燥时间t引入一个指数r,建立了气调热泵干燥过程中绿原酸降解动力学模型方程。该模型具有较好的拟合精度,可用来预测绿原酸的降解规律。

This study investigated the changes in chlorogenic acid content and exterior color of honeysuckle during modified atmosphere heat pump drying experiment. We used nitrogen as drying medium to reduce the oxygen concentration, considered the influences of drying temperature, loading and oxygen volume fraction on chlorogenic acid content and L value, and constructed the degradation kinetics model of chlorogenic acid. The results showed that chlorogenic acid content and L value at the end of drying decreased with increasing temperature, load and oxygen volume fraction. Degradation kinetics of chlorogenic acid did not follow zero order or first order reaction kinetics. The degradation kinetics model of chlorogenic acid during modified atmosphere heat pump drying was established through introducing an exponent r related to time t into the first order reaction kinetics equation. The developed model had better fitting accuracy and could be used to predict the degradation pattern of chlorogenic acid.