超声波辅助提取落叶松树皮多酚的动力学和热力学研究

Kinetics and thermodynamics characteristics of ultrasonic assisted extraction polyphenols from larch bark

本文研究了超声波辅助乙醇溶液提取落叶松树皮多酚的作用,并对其动力学和热力学性质进行了分析。结果表明,最佳提取工艺条件为:超声波功率350 W,乙醇浓度50%,料液比1∶35,提取温度70℃,此条件下的多酚得率为(81.8±2.03)mg/g。探讨了超声波功率与超声时间对多酚提取作用的影响,在实验选取的动力学模型中,当超声功率为≤300 W时,指数衰减模型1可以更好地拟合提取动力学过程(R2≥0.994 52),当超声功率为350 W时最适合的拟合模型为概率型非线性回归模型(R2=0.998 27)。超声波辅助提取落叶松树皮多酚的有效扩散系数Deff随超声波功率的增加而增大,但随超声时间的增加而减小,自由能ΔG变化表明超声波辅助提取方式更有利于传质过程的进行。

Effects of ultrasonic assisted ethanol extraction polyphenols from larch bark were investigated, and the related kinetics and thermodynamics were evaluated. The results showed that the optimum extraction process was as follows： ultrasonic power was 350 W, ethanol concentration was 50% , the ratio between the solid and liquid was 1 ： 35 and ultrasonic extraction temperature was 70 ℃ , the polyphenols yield was （81.8 ± 2.03） mg/g under the optimum conditions. Effects of ultrasonic power and time interaction on the extraction of polyphenols were discussed, the kinetic analysis indicated that the Expdecl model was the best one to fit the extraction course when ultrasonic power less than 300 W （R2 ≥ 0. 994 52） ; while the Logistic model was the best when ultrasonic power was 350 W （R2 = 0. 998 27）. The effective diffusivity coefficient value of ultrasonic assisted extraction polyphenols from larch bark was enhanced concomitantly with increasing values of ultrasonic power, while reduced with ultrasonic time increased. The variety of free energy indicated that the ultrasonic assisted extraction method could favor the mass transfer.