Antioxidant, antihypertensive and antidiabetic potential of peptidic fractions obtained from tarwi (Lupinus mutabilis) protein hydrolysate and identification of promising multifunctional bioactive peptides

Tarwi is an Andean grain, belonging to the legume group and is characterised by its high protein content, exceeding that reported in soybeans being an interesting resource for obtaining bioactive peptides. The tarwi protein hydrolysate (TPH) obtained by enzymatic hydrolysis with Alcalase (60 min) followed by Neutrase (120 min) presented important multifunctional properties to cope with oxidative stress, hypertension and diabetes. After concentration and purification process the most active fraction containing the highest antioxidant, antihypertensive (inhibition of angiotensin-converting enzyme I, ACE) and antidiabetic (inhibition of dipeptidyl peptidase IV, DPP IV) properties were found in the low-molecular weight peptide fraction. Thus, this last fraction was subjected to a de novo sequencing LC–MS/MS analysis yielding the identification of 25 peptides, with potential activities as ACE and DPP IV inhibitors and antioxidative according to BIOPEP database. Of these, four novel peptides: AVPFWM, YSGWLGL, AHAGFGMLY and FFSMKVM, stood out for their relatively high scores in bioactivity predicted by Peptide Ranker, additionally the structure–activity evaluation performed on them, supported the predicted antioxidant, antihypertensive and antidiabetic properties. These results demonstrated that TPH might be considered a potential source of peptides with multifunctional bioactive properties with possibilities of application in the food and nutraceutical sectors.