Impact of diffusion, transmembrane pressure and the electrical field on peptide fractionation using cross-flow electro membrane filtration

Downstream processes combining ultrafiltration and an applied electrical field as driving forces have recently been developed for the fractionation of peptides to obtain maximum fractionation coefficients, and thus, higher fractionation efficiency. However, the filtration mechanism and the overlaying effects of fractionation still remain unclear. To gain a better understanding of the dominating mechanism, the objective of this work was to evaluate the impact of diffusion, transmembrane pressure and the applied electrical field during cross-flow electro membrane filtration of micellar casein hydrolysate. Special emphasis was placed on the fractionation of six model peptides, which belong to the group of antihypertensive peptides. In addition, the apparent charge of the model peptides with different charges, peptide lengths and isoelectric points were calculated from experimental data and compared with those determined via the pka. The experiments revealed that the applied electrical field is an effective tool to enhance the fractionation process by 45%.