Investigation of ACE and DPP‐IV Inhibitory Potential of Peptides Obtained From Hazelnut Protein Hydrolysates in Food Supplement Applications

ABSTRACT Here, lyophilized protein hydrolysates from hazelnut cake and their valorization in food supplements were investigated. Hazelnut protein isolates were obtained by the alkali extraction‐isoelectric precipitation method. Thus, the obtained isolates were subjected to proteolysis using pepsin or bromelain and fractionated by ultrafiltration. ACE (angiotensin‐converting enzyme)‐inhibitory, DPP‐IV (dipeptidyl peptidase‐IV)‐inhibitory, or DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) radical scavenging activity tests were administered. The fraction with the highest ACE inhibitory activity (approx. 91%) was lyophilized and utilized in micropellet capsule manufacture, where capsules were dissolved, and bioactivity tests were performed. The highest ACE‐inhibitory activity was observed in aliquots taken after 30 min. While capsules also demonstrated slight DPP‐IV inhibitory activity, that was strongly enhanced during dissolution. Interactions with impurities possibly affected the dissolution behavior. Current findings showed that hazelnut cake is an important industrial by‐product for generating ACE‐inhibitor peptides and their bioactivity level renders them suitable for food supplement applications.