High‐pressure microfluidisation pretreatment disaggregate peanut protein isolates to prepare antihypertensive peptide fractions

High-pressure microfluidisation (HPM) pretreatment was applied to increase in vitro antihypertensive activity of peanut peptide fractions (PPF). The morphology of protein in aqueous dispersion revealed that peanut protein isolate (PPI) disaggregated at relatively low pressure (≤120 MPa) and re-aggregated at relatively high pressures (150–210 MPa). The treated pressure of 120 MPa could lead to the most disaggregation of PPI. Small peptides contents, trichloroacetic acid-nitrogen soluble index (TCA-NSI) and degree of hydrolysis (DH) of peanut protein hydrolysates (PPH) all reached the highest at 120 MPa. Consequently, it possessed the highest angiotensin converting enzyme (ACE) and renin inhibitory activity. The highest surface hydrophobicity occurred at 120 MPa pretreatment samples. Thirty-nine oligopeptides at 120 MPa pretreatment were identified by ultra-performance liquid chromatography-quadrupole time-of-flight (UPLC-Q-TOF) mass spectrometer combined with Progenesis QI for Proteomics software compared with 29 and 35 at control and 210 MPa, respectively. This meant that disaggregation of PPI at 120 MPa resulted in the release of new hydrophobic peptide.