循环超声提取玛咖生物碱动力学及热力学研究

研究不同温度和超声密度下循环超声提取玛咖生物碱的动力学及热力学。分别采用双指数模型和范特霍夫方程用于提取动力学过程拟合和热力学参数计算。结果表明双指数模型能较好的拟合玛咖生物碱提取过程，生物碱得率和速率常数随着温度或超声密度的增加而增加，洗涤和扩散阶段的活化能分别为16.41 kJ/mol和17.52 kJ/mol。循化超声提取过程是吸热、不可逆和自发的。与传统浸提相比，循环超声提取在20 ℃和50 ℃时，生物碱得率均显著高于传统浸提（p<0.01）。因此循环超声提取是一种高效的提取技术，可用于玛咖生物碱提取。
This study investigated kinetics and thermodynamics for the ultrasonic-circulating extraction of Lepidium meyenii Walp.（maca） alkaloids. The extraction was carried out with different temperatures or acoustic energy densities. Two site model was applied to simulate the extraction kinetics and Van't Hoff equation was used to calculate thermodynamic parameters. Results showed that two site model gave satisfactory data fit. Alkaloid yield and rate constants were enhanced with increased temperature or acoustic energy density. The activation energy values were 16.41 kJ/mol and 17.52 kJ/mol for washing and diffusion stages，respectively. The alkaloid extraction was endothermic，irreversible and spontaneous. In addition，compared with maceration，ultrasonic- circulating extraction resulted in significantly higher yields of alkaloids at 20 ℃ and 50 ℃（p<0.01）. Therefore，ultrasonic-circulating extraction is an effective technology to extract maca alkaloids