Application of lanthanum-modified silk fibroin/polyvinyl alcohol film for highly selective defluoridation in brick tea infusion

Liping Mei; Jiao Wei; Ruirui Yang; Wei Guo; Yuexin Liu; Fei Ke; Chuanyi Peng; Ruyan Hou; Guijie Chen; Junsheng Liu; Daxiang Li; Xiaochun Wan; Huimei Cai

doi:10.1016/j.ijbiomac.2025.139456

Application of lanthanum-modified silk fibroin/polyvinyl alcohol film for highly selective defluoridation in brick tea infusion

Int J Biol Macromol. 2025 Jan 2:139456. doi: 10.1016/j.ijbiomac.2025.139456. Online ahead of print.

Authors

Liping Mei¹, Jiao Wei², Ruirui Yang², Wei Guo², Yuexin Liu², Fei Ke³, Chuanyi Peng⁴, Ruyan Hou⁴, Guijie Chen⁴, Junsheng Liu⁵, Daxiang Li⁴, Xiaochun Wan⁶, Huimei Cai⁷

Affiliations

¹ State Key Laboratory of Tea Plant Biology and Utilization, Joint Research Center for Food Nutrition and Health of IHM and Anhui Provincial Key Laboratory of Food Safety Monitoring and Quality Control, Anhui Agricultural University, Hefei 230036, PR China; Hefei Technology College, Hefei 238000, PR China.
² State Key Laboratory of Tea Plant Biology and Utilization, Joint Research Center for Food Nutrition and Health of IHM and Anhui Provincial Key Laboratory of Food Safety Monitoring and Quality Control, Anhui Agricultural University, Hefei 230036, PR China; College of Food and Nutrition, Anhui Agricultural University, Hefei 230036, PR China.
³ State Key Laboratory of Tea Plant Biology and Utilization, Joint Research Center for Food Nutrition and Health of IHM and Anhui Provincial Key Laboratory of Food Safety Monitoring and Quality Control, Anhui Agricultural University, Hefei 230036, PR China.
⁴ State Key Laboratory of Tea Plant Biology and Utilization, Joint Research Center for Food Nutrition and Health of IHM and Anhui Provincial Key Laboratory of Food Safety Monitoring and Quality Control, Anhui Agricultural University, Hefei 230036, PR China; School of Tea Science, Anhui Agricultural University, Hefei 230036, PR China.
⁵ Department of Chemical and Material Engineering, Hefei University, 99 Jinxiu Avenue, Hefei 230601, PR China.
⁶ State Key Laboratory of Tea Plant Biology and Utilization, Joint Research Center for Food Nutrition and Health of IHM and Anhui Provincial Key Laboratory of Food Safety Monitoring and Quality Control, Anhui Agricultural University, Hefei 230036, PR China; School of Tea Science, Anhui Agricultural University, Hefei 230036, PR China. Electronic address: [email protected].
⁷ State Key Laboratory of Tea Plant Biology and Utilization, Joint Research Center for Food Nutrition and Health of IHM and Anhui Provincial Key Laboratory of Food Safety Monitoring and Quality Control, Anhui Agricultural University, Hefei 230036, PR China; College of Food and Nutrition, Anhui Agricultural University, Hefei 230036, PR China. Electronic address: [email protected].

PMID: 39755298
DOI: 10.1016/j.ijbiomac.2025.139456

Abstract

To mitigate the risk associated with water-soluble fluoride in tea and to have less influence on the contents of tea infusion, a highly selective lanthanum modified silk fibroin (SF) and polyvinyl alcohol (PVA) composite film (SF/PVA-La) was prepared to remove fluoride from brick tea infusion. Notably, SF/PVA-La could remove about 48 % of the fluoride from in brick tea infusion within 30 min. Importantly, the reduction in total tea polyphenols in brick tea did not exceed 10 %, and the reduction in caffeine was only 0.4 %. In addition, the Langmuir model revealed a maximum fluoride adsorption capacity of 9.15 mg/g for SF/PVA-La in brick tea infusion. Both FTIR and XPS analyses confirmed that SF/PVA-La engages in electrostatic adsorption of fluoride ions, with ion exchange occurring between the hydroxyl groups on its surface and the fluoride ions. These findings underscore the potential of SF/PVA-La as an effective material for selective fluoride removal from brick tea infusions.

Keywords: Brick tea; Fluoride removal; Selective adsorption; Tea polyphenols.