Effects of applied current modes on the migration selectivity of peptides from a porcine cruor hydrolysate during electrodialysis with ultrafiltration membrane

Pepsic hydrolysis of porcine hemoglobin produces various antimicrobial peptides, however, within such complex hydrolysates, certain peptide bioactivities remain unexpressed. Electrodialysis with ultrafiltration membrane (EDUF) addresses this by separating peptides from hydrolysates based on peptide charge and molecular mass, resulting in fractions with increased bioactivity. This study aims to assess the impacts of different current modes (continuous current (CC), pulsed electric field (PEF) and polarity reversal (PR)) on peptide migration selectivity, which has never been reported. Different combinations of pulse and pause or reversed pulse were tested: 1 s/1 s and 10 s/1 s. This investigation focused on the 31 most migrating peptides and their 6 main physicochemical characteristics. Three groups of current conditions with similar performances were observed: 1) CC, PEF 10 s/1 s and PR 10 s/1 s (Averaged final migration rate of 5.0 g/m2.h and energy consumption of 48.7 Wh/g of peptide); 2) PEF 1 s/1 s (9.0 g/m2.h and 61.0 Wh/g of peptide), and 3) PR 1 s/1 s (3.3 g/m2.h and 95.6 Wh/g of peptide). CC, PEF, and PR 10 s/1 s facilitated the migration of mainly cationic peptides with low molecular masses and were the most selective conditions. High ratio of pulse/pause or pulse/reversed pulse minimized or have no interference on peptide migration selectivity and the migration of neutral or negative peptides was due to peptide-peptide interactions. These results demonstrated for the first time the significant impact of the electrical current mode and conditions on migration selectivity during EDUF, opening a new avenue to influence the final bioactivity or population of the separated fractions.