Effect of pressure or temperature pretreatment of isolated pea protein on properties of the enzymatic hydrolysates

•100 °C pretreated isolated pea protein (IPP) had increased surface aromatic groups.•High pressure (600 MPa) pretreated IPP had reduced exposure of aromatic groups.•400 and 600 MPa-pretreated IPP were less digested at low alcalase concentrations.•Heat pretreatment of IPP reduced ACE-inhibition by the alcalase hydrolysates.•High-pressure pretreatment of IPP increased renin inhibition by hydrolysates.

Commercial isolated pea protein dispersion (IPP, 1%, w/v) was pretreated with high pressure (200-600 MPa, 5 min at 24 °C) or heat (100 °C, 30 min) prior to hydrolysis using 1-4% (w/w) alcalase concentrations. Fluorescence spectroscopy showed that heat pretreated IPP had a 35% higher level of exposed hydrophobic groups (measured as fluorescence intensity, FI) than the untreated protein. In contrast, the 200 MPa pressure pretreatment produced a 15% increase in FI while 400 and 600 MPa pretreatments, respectively, caused 5 and 60% decreases in FI. Heat pretreatment of IPP enhanced hydrolysis into smaller peptide sizes when compared to peptides from the 24 °C pretreated protein. The 200 MPa pretreatment enhanced IPP hydrolysis into smaller peptides, especially at lower (1-2%) alcalase concentrations. Protein hydrolysates produced from heat-pretreated IPP were less active against angiotensin converting enzyme (ACE) when compared to those from the 24 °C pretreated protein. In general, heat or high pressure pretreatment of IPP favored production of ACE- and renin-inhibitory enhanced protein hydrolysates at a lower (1%) alcalase concentration.