Impact of soybeans maturation stage on the release of dipeptidyl peptidase-4 and pancreatic α-amylase inhibitory peptides from soybean protein

This study investigated the impact of maturation stage on the generation of α-amylase (AA) and dipeptidyl peptidase 4 (DPP-4) inhibitory peptides. Overall, results obtained revealed higher hydrolysis of mature soybean proteins by alcalase and green soybean proteins by bromelain. Flavorzyme-derived hydrolysates showed consistently higher AA and DPP-4 inhibitory activities. Among GSPHs, F2 was most potent (IC50: 26.57 μg/mL for AA, and 29.26 μg/mL for DPP-4), while F4 excelled among MSPHs (IC50: 36.79 μg/mL for AA, and 32.63 μg/mL for DPP-4). In total, 18 and 25 were identified as biologically active from GSPHs and MSPHs, respectively. CFAAPEGPL and AIPVNKPGRF (from GSPHs), and SFFFPFELPRE and FAGVVPAPLCCAT (from MSPHs) were most potent AA and DPP-4 inhibitors. Overall Peptide, SFFFPFELPRE with its lowest HPEPDOCK scores, remarkable binding poses, lowest binding energies against AA and second best against DPP-4 showed its anti-diabetic potential against both tested enzymes. Further, i n silico physicochemical tests and gastrointestinal digestion predicted good water solubility for AIPVNKPGRF and SFFFPFELPRE with all peptides and their fragments meeting drug-likeness criteria and were predicted to be non-toxic, except FAGVVPAPLCCAT. Overall, results indicated the potential of green and mature soybean protein-derived hydrolysates as AA and DPP-4 inhibitors.