Impact of Stacking Ultrafiltration Membranes with Different Molecular Weight Cut-Offs On the Selective Fractionation of Flaxseed Protein Hydrolysate by Electrodialysis with Ultrafiltration Membranes

A flaxseed protein hydrolysate (FPH) was fractionated by electrodialysis with ultrafiltration membranes (EDUF) for the recovery of specific peptides. The cell configuration was composed of ion-exchange membranes and two ultrafiltration membranes with different molecular weight cut-offs (20 and 50 kDa). This configuration allowed the recovery of two specific cationic peptide fractions (KCl-F1 and KCl-F2). After 360 min of treatment, EDUF allowed concentration of the 300-400 and 400-500 Da molecular weight range peptides in the KCl-F1 and KCl-F2 fractions compared to the initial FPH. Amino acid analysis showed that His, Lys and Arg were especially concentrated in the KCl-F1 and KCl-F2 compartments. Finally, glucose-transport assay demonstrated that the KCl-F2 fraction increased glucose uptake in L6 cells. Consequently, the stacking of ultrafiltration membranes with two different molecular weight cut-offs in an electrodialysis cell allowed the recovery and the concentration of more specific peptide fractions and, amongst peptide fractions recovered, specific peptide sequence(s) increased glucose uptake in L6 cell.