Antihypertensive Potential and Bioavailability of Peanut Protein Hydrolysate Derived from Partially Defatted Peanut Flour

This study evaluated the changes in angiotensin I-converting enzyme (ACE)-inhibitory activity and the secondary structure of peanut protein hydrolysate (PPH) during simulated gastrointestinal (GI) and serum digestions. The antihypertensive potential of PPH was validated using a spontaneously hypertensive rat (SHR) model. The PPH was produced by extensive Alcalase hydrolysis of peanut protein concentrate (PPC) and was digested by simulated gastric, intestinal, and sequential digestions, respectively. SDS-PAGE showed that PPH was relatively resistant to GI digestion. Higher single-enzyme concentration and longer digestion time increased the ACE inhibition of PPH, while sequential digestion did not change it significantly. In serum, the ACE inhibition of PPH persisted for at least 30 min, indicating that PPH peptides reaching the circulation may remain active for this period, but most of this activity was lost by 180 min. In SHRs, PPH at an oral dose of 1000 mg/kg body weight/day attenuated the rise in mean arterial pressure comparable to captopril. FT-IR demonstrated that sequential digestion reduced relative α-helices but increased β-sheet, β-turn, and random coil contents in PPH. Overall, PPH shows promise as a functional food or dietary supplement for blood pressure management. For hypertensive adults with 60 kg body weight, consuming PPH at a dose of 9.7 g per day may help control their blood pressure.