Kinetic study of subcritical water extraction of flavonoids from citrus unshiu peel
Kinetic study of subcritical water extraction of flavonoids from citrus unshiu peel
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DOI：
10.1016/j.seppur.2020.117259
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发表时间：
2020-11-01
影响因子：
8.6
通讯作者：
Lim, Sang-Bin
中科院分区：
文献类型：
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作者：
Kim, Dong-Shin;Lim, Sang-Bin
柑橘皮是许多重要的黄酮类化合物的主要来源，黄酮（橙皮苷和水杨柳素）和多甲氧基黄酮（PMFs；柑桔素，白杨素和橘子素），它们具有抗氧化，抗炎，抗癌和保护心脏的特性。研究了亚临界水在不同温度（120 ~ 180℃）和流速（1.0 ~ 2.0 mL/min）下对柑桔黄酮类化合物提取率的影响机制。橙皮苷、纳瑞芦丁和PMFs的提取率分别从120℃时的40.9%、69.0和67.4%提高到160℃时的79.6、81.9和89.0%，而在180℃时则发生分解。利用不同流速下的提取率曲线，确定了用热力学分配模型还是动力学解吸模型来描述提取效果最好。萃取速率曲线显示，萃取初期为快速萃取阶段，萃取后期为缓慢萃取阶段。萃取后期的热力学分配模型与实验数据不匹配。两点动力学解吸模型很好地拟合了整个提取周期，表明柑橘类黄酮的提取主要受颗粒内扩散控制。有趣的是，即使在热解温度（180℃）下，该模型也很适合。因此，双向动力学模型可以很好地描述SW对柑橘类黄酮的分解机理和提取机理。160℃、2 mL/min时橙皮苷的扩散系数比120℃、1 mL/min时增大了9.8倍。橙皮苷的活化能（37.2 ~ 43.8 kJ/mol）高于纳瑞芦丁和PMFs的活化能（8.2 ~ 36.8 kJ/mol）。本研究表明，提取机制主要受颗粒内扩散的影响，使用少量的环保型溶剂SW可在短时间内较好地回收柑橘皮中的黄酮类化合物。
Citrus peels are the main source of many important flavonoids, flavanones (hesperidin and narirutin) and polymethoxyflavones (PMFs; sinensetin, nobiletin, and tangeretin), which have antioxidant, anti-inflammatory, anticancer, and cardioprotective properties. In this study, the mechanisms controlling the extraction rates of flavonoids from Citrus unshiu peel using subcritical water (SW) were studied at different temperatures (120-180 degrees C) and flow rates (1.0-2.0 mL/min). The extraction yields increased from 40.9, 69.0, and 67.4% at 120 degrees C to 79.6, 81.9, and 89.0% at 160 degrees C for hesperidin, narirutin, and PMFs, respectively, while decomposition occurred at 180 degrees C. The extraction rate curves at different flow rates were used to determine whether the extraction was best described by a thermodynamic partitioning or kinetic desorption model. The extraction rate curves showed that the initial extraction phase is fast, while the subsequent phase is slow. The thermodynamic partitioning model did not match with the experimental data for the latter part of the extraction period. The two-site kinetic desorption model fit the entire extraction period very well, suggesting that the extraction of citrus flavonoids was mainly controlled by intra-particle diffusion. Interestingly, this model fit well even at the pyrolysis temperature (180 degrees C). Therefore, the two-site kinetic model can well describe both the decomposition mechanism and extraction mechanism of citrus flavonoids when using SW. The diffusion coefficient of hesperidin increased about 9.8-fold at 160 degrees C and 2 mL/min relative to 120 degrees C and 1 mL/min. The activation energy of hesperidin (37.2-43.8 kJ/mol) was higher than those of narirutin and PMFs (8.2-36.8 kJ/mol). This study showed that the extraction mechanism is mainly affected by intra-particle diffusion, and that use of small amounts of SW, an environmentally friendly solvent, promotes good recovery of flavonoids from citrus peel in a short time.