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

Abstract

Commercial isolated pea protein dispersion (IPP, 1%, w/v) was pretreated with high pressure (200–600MPa, 5min at 24°C) or heat (100°C, 30min) 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 200MPa pressure pretreatment produced a 15% increase in FI while 400 and 600MPa 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 200MPa 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.