Identification of angiotensin‐converting enzyme inhibitory peptides from peanut meal (Arachis hypogaea Linn) fermented by Lactobacillus pentosus using MALDI‐TOF–MS and LC–MS/MS

Abstract This study focused on the production of angiotensin‐converting enzyme inhibitory peptides (ACEIPs) from peanut meal (Arachis hypogaea Linn) fermented by Lactobacillus pentosus. The fermentation process was optimized using the response surface methodology with ACE inhibitory activity as the experimental indicator. ACEIPs were further purified after fermentation using ultrafiltration and Sephadex G‐25 gel chromatography. The effect of different molecular weights (ranging from 0.5 to 1.5 kDa) of ACEIP on ACE inhibitory activity was investigated, and a maximum inhibitory rate of 48.83% was achieved. The content of ACEIP was 78.95%. Amino acid analysis revealed that the hydrophobic amino acids accounted for 43.09% of the total content. Among the identified amino acids, glutamic acid had the highest content of 14.94%, followed by leucine and aspartic acid. Matrix‐assisted laser desorption/ionization time‐of‐flight–mass spectrometry (MS) and liquid chromatography–tandem MS were used to identify the molecular weights of the selected ACEIPs, yielding six ACEIPs with good stability and high hydrophilicity. Flexible docking of the six ACEIPs with ACE was simulated using AutoDock Vina (v1.5.7). The result showed that the ACEIPs formed 11, 8, 7, 9, 7, and 6 hydrogen bonds with ACE residues, and the lowest binding energies between them were −9.8, −8.1, −9.0, −9.3, −8.2, and−9.1 kcal/mol, respectively. Among them, GFGINAENNHRIF exhibited superior ACE inhibitory activity and binding stability.