Exploring electrodialysis with bipolar membranes for water lentil (duckweed) protein purification: A first investigation into process and membrane characterization with products comparison to chemical acidification

Water lentils are free-floating aquatic plants which could be an inexpensive source of protein due to their high leaf protein content and very rapid reproduction. However, the extraction and purification of leaf proteins from their matrix is a necessary step for human consumption, as undesired compounds can reduce their functional or sensorial properties. Therefore, in this study, water lentil proteins were purified for the first time using electrodialysis with bipolar membrane (EDBM), a technology that has been developed as an ecofriendly alternative to chemical acidification. The EDBM of water lentils successfully produced a protein concentrate that had a similar protein content (approximately 47.7 g/100 g) and protein extraction yield (around 39.4 %) compared to chemical precipitation. Moreover, EDBM allowed the demineralization of the protein concentrate by-product compared to chemical precipitation, reducing by 74 % its ash content (58.4 vs 15.2 g/100 g) and doubled its protein content (20.5 vs 41.1 g/100 g). However, during the EDBM process, the system's resistance tripled, and protein deposits were observed inside spacers and on bipolar membrane cation-exchange layer. Hence, while EDBM shows great promise, further optimization is necessary to enhance process efficiency.