Phospholipid recovery from sweet whey by combination of electrodialytic processes and understanding of specific mechanisms involved

Electrodialysis with bipolar membrane (EDBM) combined with a subsequent 4-6 fold dilution was demonstrated to allow high phospholipid (PL) recovery and defatting rate. However, the economic and environmental draw-backs of such dilution limit the process application in the food industry. To overcome them, original combinations of treatment with EDBM, applicable in the food industry (demineralization by conventional electrodialysis (ED) and diafiltration), were tested for the first time and compared with the EDBM + dilution process. The most promising combination was the EDBM + ED process. Indeed, demineralization by ED after EDBM allowed to reach the highest divalent cation removal (70.2 % versus 2.3 and 39.7 % respectively for dilution and diafiltration) and defatting rate (76.6 % versus 54.2 and 23.0 % respectively for dilution and diafiltration). Furthermore, this combination allowed to concentrate phosphatidylethanolamine by 15 X compared to its content in initial sweet whey and to reach the highest PL yield (25.9 g/100 L of sweet whey versus 13.3 and 8.99 g/100 L respectively for dilution and diafiltration). These high performances were associated with different phenomena occurring during the treatments performed after EDBM and leading to specific impacts on ionic strength, mineral content and composition. From those phenomena, it was possible to under-stand the key role of the removal of divalent cations in the formation of lipoprotein complexes, highlighting that it was not only due to the reduction in pH and ionic strength. Consequently, EDBM combined with ED appears to be an attractive industrial process, as it combined the ecofriendly advantages of electrodialytic technics, while limiting water consumption, avoiding the production of large volumes of effluents and the use of chemical agents.