Decoding bioactivity in pea proteins: optimised hydrolysis reveals antioxidant and ACE-inhibitory peptides

Pea proteins can be converted into health-promoting ingredients through enzymatic hydrolysis. This study systematically investigates the effect of different degrees of hydrolysis (DH), namely limited (DH < 10 %), intermediate (10 % < DH < 20 %), and extended (DH > 20 %), on the antioxidant properties (assessed via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays.) and Angiotensin-Converting Enzyme (ACE)-inhibitory activities of pea protein hydrolysates (PPHs) obtained using Alcalase 2.4L. Moreover, the impact of a filtration step applied to isolate peptides below 3 kDa on biological properties was also studied. Enzymatic hydrolysis enhanced all bioactivities, but antioxidant properties peaked at intermediate hydrolysis, while ACE-inhibitory activity increased progressively with hydrolysis degree. In both cases, peptides with a molecular weight below 3 kDa were primarily responsible for the detected bioactivities. Distinct peptides, accurately sequenced by high-performance liquid chromatography coupled with electrospray ionisation tandem mass spectrometry (HPLC-ESI-MS/MS), were associated with each activity. Particularly, GFFC contributed to radical scavenging, while YDFXMF was linked to ACE inhibition. These findings highlight the importance of optimising hydrolysis conditions to maximise specific bioactivities. This approach supports the development of sustainable, functionally targeted pea-derived ingredients.