Comparative Study of in Situ and ex Situ Enzymatic Hydrolysis of Milk Protein and Separation of Bioactive Peptides in an Electromembrane Reactor

Abstract

Tryptic hydrolysis of whey protein isolate was performed simultaneously during (in situ) and before (ex situ) fractionation by electrodialysis with ultrafiltration membrane (EDUF) to obtain bioactive peptides. Peptide migration to anionic (ARC–) and cationic (CRC+) peptide recovery compartments was strongly dependent on the digestion strategy used. Indeed, peptide migration to the ARC– was observed to be higher with in situ digestion while peptide migration to the CRC+ was higher in an ex situ digestion: a final peptide concentration of 103.10 ± 2.76 μg/mL was found in the CRC+ (ex situ) while it was 49.65 ± 6.13 μg/mL in the ARC– (in situ). HPLC-MS studies showed 23 major peaks that were generated by tryptic digestion of whey protein isolate. Seven of these peptides migrated to the ARC– while nine and eight peptides migrated to the CRC+ for ex situ and in situ digestions, respectively. Among them, different antihypertensive, antimicrobial, and hypocholesterolemic peptides were recovered depending on the ...