Exploring the modulation of peptide migration and fraction bioactivity by electrical current modes during electrodialysis with ultrafiltration membrane: A comprehensive machine learning-peptidomic study

Enzymatic hydrolysis of coproducts, by generating bioactive peptides, is a promising valorization avenue to produce high added-value new products, in a context of a circular economy. Bioactivities of such complex solutions can be limited by the mix with all the other peptides. Electrodialysis with ultrafiltration membrane (EDUF), combining separation based on the charge and the molecular mass, is an eco-efficient strategy to obtain peptide fractions with enhanced bioactivities and greater purity. While continuous electrical current (CC) is conventionally applied, alternative modes like pulsed electric field (PEF) and polarity reversal (PR) offer opportunities to modify selectivity, decrease fouling, and energy consumption. No study ever focused specifically on the effects on peptide migration rates. In this context, five electrical current conditions were explored - CC, PEF ratio 1 and 10, and PR ratio 1 and 10 - on a well-characterized porcine cruor hydrolysate, which is a part of porcine blood. Using UPLC-MS/MS, migration rates were calculated for each peptide, under the different electric current conditions. Bioinformatic tools were used to extract 41 physicochemical characteristics from each peptide, and a machine learning approach, employing regression tree procedures, to establish connections between peptide migration rates, physicochemical characteristics, and specific electrical current conditions. Results revealed distinct root nodes, with molecular mass identified as major for PR 1, and pI for CC, PEF 10, and PR 10. PEF 1 exhibited an intermediate regression tree. Comparisons between trees facilitated the assessment of similarities among electrical current conditions and prediction of key physicochemical parameters influencing the migration of peptides. They allowed some tentative explanations of the phenomena involved, such as effects on the diffusion boundary layer. Antimicrobial activities were also assessed, and allowed to demonstrate for the first time how the electrical current conditions, by modifying the peptide migration, modulated the antimicrobial activities, either towards antifungal or antibacterial.