volume | PIER Journals

Abstract

Microwave-assisted extraction (MAE) is an effective method for extracting tea polyphenols. However, research on MAE mainly focuses on experimental methods, which not only leads to a large amount of experimental work but also generates a lot of material waste. In addition, due to the lack of mechanism research, it is difficult to find a more effective method. In this study, based on electromagnetic field theory, the heat and mass transfer model of tea polyphenol extraction is established based on measuring the dielectric properties of the extract. The distribution of temperature, diffusion coefficient, and flow rate of microwave-assisted extraction of tea polyphenols are all analyzed in detail. The results show that the temperature distribution in the extraction system is uneven. The middle temperature of the extraction solution is high and the edge is low. Moreover, with the increase of microwave power and extraction temperature, the diffusion coefficient is gradually increased, and the flow rate increases, which is more conducive to the extraction process as time goes by. This study provides a theoretical basis for the microwave-assisted extraction of tea polyphenols, reducing experimental workload and material waste.

1. Yan, Zhaoming, Yinzhao Zhong, Yehui Duan, Qinghua Chen, and Fengna Li, "Antioxidant mechanism of tea polyphenols and its impact on health benefits," Animal Nutrition, Vol. 6, No. 2, 115-123, Jun. 2020.
doi:10.1016/j.aninu.2020.01.001

2. Sun, Mu-Fang, Chang-Ling Jiang, Ya-Shuai Kong, Jin-Lei Luo, Peng Yin, and Gui-Yi Guo, "Recent advances in analytical methods for determination of polyphenols in tea: A comprehensive review," Foods, Vol. 11, No. 10, 1425, May 2022.
doi:10.3390/foods11101425

3. Li, Gang-Feng, Hui-Xi Wang, Shi-Xue Chen, Rong Fu, and Bei Huo, "Study on microwave-assisted extraction of low-grade green tea polyphenols," Cereals & Oils, Vol. 28, No. 1, 60-62, 2015.

4. Mojzer, Eva Brglez, Masa Knez Hrncic, Mojca Skerget, Zeljko Knez, and Urban Bren, "Polyphenols: Extraction methods, antioxidative action, bioavailability and anticarcinogenic effects," Molecules, Vol. 21, No. 7, 901, Jul. 2016.
doi:10.3390/molecules21070901

5. Xu, F. F., B. D. Zhu, G. W. Jiang, X. Y. Yu, and X. Q. Sang, "Advances in tea polyphenol extraction methods and pharmacological effects," J. Mod. Med. Health, Vol. 28, No. 7, 1033-1035, 2012.

6. Coelho, Jose P., Maria P. Robalo, Stanislava Boyadzhieva, and Roumiana P. Stateva, "Microwave-assisted extraction of phenolic compounds from spent coffee grounds. Process optimization applying design of experiments," Molecules, Vol. 26, No. 23, 7320, Dec. 2021.
doi:10.3390/molecules26237320

7. Chong, Chuanyin, Tao Hong, and Kama Huang, "Design of the complex permittivity measurement system based on the waveguide six-port reflectometer," IEEE Transactions on Instrumentation and Measurement, Vol. 71, 1-12, 2022.
doi:10.1109/TIM.2022.3172425

8. Xue, H. K., J. Q. Tan, X. Cai, C. H. Liu, J. T. Tang, and Q. Li, "Effect of microwave power on the extraction process of anthocyaninfrom cranberry," Food Science, Vol. 43, No. 1, 92-101, 2022.

9. Zhou, Jie, Xiaoqing Yang, JingHua Ye, Huacheng Zhu, Jianping Yuan, Xun Li, and Kama Huang, "Arbitrary Lagrangian-Eulerian method for computation of rotating target during microwave heating," International Journal of Heat and Mass Transfer, Vol. 134, 271-285, 2019.

10. Yan, Jian, Xiaoqing Yang, and Ka-Ma Huang, "Numerical analysis of the influence of stir on water during microwave heating," Progress In Electromagnetics Research C, Vol. 17, 105-119, 2010.

11. Ye, Jinghua, Junqing Lan, Yuan Xia, Yang Yang, Huacheng Zhu, and Kama Huang, "An approach for simulating the microwave heating process with a slow-rotating sample and a fast-rotating mode stirrer," International Journal of Heat and Mass Transfer, Vol. 140, 440-452, Sep. 2019.
doi:10.1016/j.ijheatmasstransfer.2019.06.017

12. Zhu, Huacheng, Jianbo He, Tao Hong, Qianzhen Yang, Ying Wu, Yang Yang, and Kama Huang, "A rotary radiation structure for microwave heating uniformity improvement," Applied Thermal Engineering, Vol. 141, 648-658, Aug. 2018.
doi:10.1016/j.applthermaleng.2018.05.122

13. Yanniotis, S. and N. G. Stoforos, "Modeling food processing operations with computational fluid dynamics: A review," Scientia Agriculturae Bohemica, Vol. 45, No. 1, 1-10, 2014.
doi:10.7160/sab.2014.450101

14. Hossan, Mohammad Robiul, Do Young Byun, and Prashanta Dutta, "Analysis of microwave heating for cylindrical shaped objects," International Journal of Heat and Mass Transfer, Vol. 53, No. 23-24, 5129-5138, Nov. 2010.
doi:10.1016/j.ijheatmasstransfer.2010.07.051

15. Bi, Gening, Xiaohua Xiao, and Gongke Li, "Development and validation of multiple physical fields coupling model for microwave-assisted extraction," Chemical Journal of Chinese Universities, Vol. 43, No. 3, 56-66, Mar. 2022.
doi:10.7503/cjcu20210739

Ms. Dan Li

Dr. Tao He

Dr. Boyu Li

Dr. Ziqin Wang

Dr. Zhengming Tang