Inhibitory properties of Bambara groundnut protein hydrolysate and peptide fractions against angiotensin converting enzymes, rennin and free radicals

Abstract

BACKGROUND:Anincreasedrateofhighbloodpressurehasledtocriticalhumanhypertensiveconditionsinmostnations.Inthepresentstudy,bambaraproteinhydrolysates(BPHs)obtainedusingthreedifferentproteases(alcalase,trypsinandpepsin)and theirpeptidefractions(molecularweight:10,5,3and1kDa)wereinvestigatedforantihypertensiveandantioxidantactivities. RESULTS:Alcalasehydrolysatecontainedthehighestamountoflowmolecularweight(LMW)peptidescomparedtopepsinand trypsinhydrolysates.LMWpeptidesfractions(<1kDa)exhibitedthehighestinhibitoryactivityagainstangiotensin-converting enzyme (ACE) for all the enzymes hydrolysates. For renin inhibition, alcalase hydrolysate showed the highest inhibition at 59%comparedtootherhydrolysatesandtheircorrespondingmembranefractions.Theantioxidantpowerofbambaraprotein hydrolysates and peptide fractions was evaluated through the inhibition of linoleic acid peroxidation and ABTS scavenging activity.Amongthehydrolysates,alcalaseexhibitedthehighestinhibitionoflinoleicacidoxidation.Furthermore,allBPHswere abletoscavengeABTS•+ to a three fold greater extent compared to the isolate. CONCLUSION: BPH and LMW peptide fractions could potentially serve as useful ingredients in the formulation of functional foods and nutraceuticals against high blood pressure and oxidative stress