微波辅助萃取蓝莓花青素获取和降解的动力学模型

Kinetic models of extraction and degradation of anthocyanins from blueberry by microwave assisted extraction

中文关键词:  微波萃取  蓝莓  花青素  动力学

英文关键词:microwave extraction  blueberry  anthocyanins  kinetics

中文摘要:

      目的 同步表征微波辅助萃取(microwave-assisted extraction, MAE)蓝莓过程中花青素获取和降解过程。方法 依据Fick第二定律建立蓝莓花青素微波辅助萃取过程的动力学模型, 并对模型进行修正, 最终得到能同步表征花青素获取和降解的动力学模型。采用Origin 9.0软件中的Levenberg-Marquardt优化算法模型进行求解, 同时采用简单的测定提取分配系数的方法计算热力学函数焓变(ΔH)、熵变(ΔS)和自由能变(ΔG)。通过扫描电镜观察蓝莓颗粒细胞的微观结构。结果 拟合的动力学模型与实验结果拟合较好。萃取速率常数(k1)和降解速率常数(k2)均随萃取温度升高而增大。ΔH和ΔS分别为9.32 kJ/mol和85.51 J/mol, 两者均大于零, 说明MAE蓝莓花青素是一个吸热熵增加的过程。ΔG小于零, 说明MAE过程是一个自发过程。观察蓝莓细胞的微观结构, 发现经微波处理后蓝莓细胞结构遭到严重破坏, 细胞壁破裂, 而经过热回流的蓝莓细胞结构保存完好, 证明微波效应加快花青素的萃取过程。结论 本研究结果可为高效提取花色苷提供参考。

英文摘要:

      Objective To simultaneously characterize the process of anthocyanins extraction and degradation in the process of microwave-assisted extraction (MAE). Methods A kinetic model of MAE anthocyanins from blueberry was established based on Fick's second law to simultaneously characterize the process of anthocyanins extraction and degradation in MAE, and the model was modified to obtain a kinetic model which could simultaneously characterize the extraction and degradation of anthocyanins. The model of Levenberg-Marquardt optimization algorithm in origin 9.0 software was used to solve the problem. At the same time, the enthalpy change (ΔH), entropy change (ΔS) and free energy change (ΔG) of thermodynamic functions were calculated by simple determination and extraction of partition coefficient. The microstructure of blueberry granulosa cells was observed by scanning electron microscope. Results The kinetic model fitted well with the experimental results. The extraction rate constant (k1) and degradation rate constant (k2) increased with the increase of extraction temperature. The values of ΔH and ΔS were 9.32 kJ/mol and 85.51 J/mol, respectively, both of which were greater than zero, indicating that MAE blueberry anthocyanins were a process of endothermic entropy increase. ΔG less than zero indicated that MAE process was a spontaneous process. By observing the microstructure of blueberry cells, it was found that the cell structure of blueberry was seriously damaged after microwave treatment, and the cell wall was broken. The cell structure of blueberry after heat reflux was well preserved, which proved that the microwave effect accelerated the extraction process of anthocyanins. Conclusion This study provides reference for the efficient extraction of anthocyanins.